Choosing computer hardware is really all about trade-offs. For the kind of work I do these days once a machine has an SSD in it nearly anything will get me the performance I need. So I start to look towards creature comforts—the keyboard and screen are the gateways from the physical world into the machine, and for the amount of time I spend with them, it makes sense to get the best that money can buy. This rules out glossy screens and the low-resolution laptop displays that have become ubiquitous in recent years, so my options have been limited.
Last year I took a chance on a new laptop: the Samsung Series 9 wooed me with its bright, relatively high-resolution matte screen, and I took a chance on it even knowing that its keyboard was a step backwards. This turned out to be a mistake for me—the trend of thinness over all else forced its designers into some unfortunate compromises around the keyboard. There just isn't enough room on an ultrabook for keys that have a comfortable travel, to speak nothing of the response. So I went back to my 2009-era Thinkpad with its adequate screen and decent keyboard, since newer Thinkpads sported brighter screens but significantly fewer pixels.
It wasn't always this difficult to find nice keyboards. Relentless cost-cutting has pushed manufacturers towards keyboards built mostly out of rubber underneath the caps and forced quality key switches to a niche populated mostly by gamers and obsessive programmers like me. But if you're willing to do some digging, you can find some fantastic options. The standard bearer here for a long time has been the venerable IBM Model M with its buckling spring mechanism. Though IBM hasn't sold them since the mid-90s, many extant keyboards from that time are still in daily use. They offer a solid, tactile response that evokes a passionate fondness in their users.
I'd heard the breathless enthusiasm with which the fans spoke of their gear, but I'd delayed taking the plunge myself because I've never been comfortable on the standard form factor shared by nearly all mechanical keyboards. After being hit by RSI in college, I went from the ergonomic-but-cheap Microsoft Natural keyboard to the good-for-a-rubber-dome Kinesis Freestyle, which had a lousy key response but was the best I could find for under US$100. For a long time the only mechanical split keyboard I could find was the legendary Kinesis Advantage, which apart from its US$300 price tag kept me at bay due to its massive size—I work from local coffee shops frequently, and the Advantage is just too clunky to toss in a bag and tote around.
But over the summer someone on the #emacs freenode channel brought my attention to the mysterious Ergodox project.
The Ergodox is a project to create a freely-licensed ergonomic mechanical keyboard design that can be built by anyone. The site, while very sparse on details of what's really going on, contains links to everything you need to source and assemble your own keyboard. Apart from a parts list, the schematics for the printed circuit board are freely downloadable and GPL-licensed. The casing comes in 3D-printed and laser-cut acrylic variants you can have constructed at your local maker space, and the firmware is on GitHub.
This is great news for the adventurous maker, but I've only got the most basic experience building electronics. Sourcing all those parts and getting the circuit board printed myself felt daunting. Luckily I discovered a company called Massdrop was organizing group buys which could get all the parts needed at a significant discount. The only problem was the group buys only opened up for a limited time, and there was a pretty serious turnaround time before delivery. As my luck had it I got in on a group buy which hit some snags in the fulfillment process and ended up having to wait from August to December for my kit to arrive. (I later found out there's another group buy to get just the circuit boards, which would have been an interesting way to go.) But to my great delight it finally came last week.
For the drop I participated in Massdrop offered an optional partial assembly service. For a small fee the board would have all the diodes and the microcontroller pre-soldered, so you'd only have to solder the switches. Since the diodes are of the tiny surface-mount variety, previous bad experience with surface-mount components prompted me to opt for the partial assembly. This ended up resulting in several extra weeks of delay, and for the most recent drop the assembly options have not been offered. But once I got my kit, soldering the switches only took around an hour. After another ten minutes I had all the caps on (with some help as pictured) and the case assembled and was ready to roll. I've heard reports of others that were new to soldering were able to handle the SMD diodes without too much trouble, so maybe my concern was unwarranted. But adding in time for the diodes does bring the total assembly time up to five or six hours. Massdrop provides detailed instructions covering the assembly process, and various users have created video tutorials as well.
I mentioned the hackable firmware earlier—this is really one of the things that sets the Ergodox apart. The keyboard embeds a Teensy 2 board, an 8-bit Arduino-compatible microcontroller with more processing power than the computers that took the Apollo projects to the moon. Massdrop helpfully provides a fantastic web-based configuration tool that can compile and spit out firmware for the microcontroller based on the keys you've specified.
I've got it configured with a basic dvorak layout with several of my more commonly-used function keys around the edges of the thumb clusters. As a lisp hacker it was exciting for me to have unshifted parentheses keys on my thumbs. As a Paredit user I put the open paren closer to the thumb resulting in a weird-looking backwards configuration, because I rarely hit the close paren key. (Unfortunately unshifted parentheses can't be added in the web configurator; you have to patch and build the firmware yourself. I had a Teensy development environment set up from a previous project so this wasn't a big deal for me, but the convenience of the web configurator is very much appreciated when getting started.) Having enter and backspace on the thumbs is handy, but I found the outer layer of the thumb cluster is too far to hit when touch-typing, so putting my music controls there made sense. The code also supports shifting to other layers if you need more space. So far I've been comfortable with mostly just one layer, but I have a second layer with the full set of function keys and arrows for the rare occasions when those are needed.
The feel of a keyboard is obviously a really subjective thing. There's no one-size-fits-all, but the Cherry MX blue switches are really growing on me and already bring me some disappointment when I have to go back to my internal Thinkpad keyboard. But the layout takes a lot of getting used to. In particular the fact that it's staggered vertically instead of horizontally makes for an awkward adjustment period. Early typewriter designers staggered each row in order to avoid jams when the levers came up to strike the paper. Like many other quirks of early technology, this design has stuck around far longer than the reasons behind it. The Ergodox staggers each column instead in order to match up with human physiology: each finger is of a different length, so the column for the middle and longest finger is shifted up a bit higher, etc. It makes a lot of sense, but even after several days of on-and-off usage I still make lots of typos on the bottom row of my left hand. Though it's more effective to move lots of things over to the thumbs, I recommend leaving things like control, tab, and shift where you're used to them until you get over the disorientation of the new alignment.
The Ergodox project appeals to me on a lot of levels: the open licensing, the customizablility, the hands-on electronics, and the unconventional, human-oriented design. It's probably not for everyone, but if you've a professional programmer who's never given your keyboard a second thought, maybe it's time to broaden your horizons. They should be opening up the group buy for another batch in the near future...
Update: I've designed by own keyboard, which is meant to be a smaller, more travel-friendly complement to the Ergodox that shares a lot of its characteristics.
 Though I can hardly stand the mushy key response these days, I have a soft spot in my heart for the MS Natural 4000 since it brought me significant relief from my RSI symptoms. Using it for several months taught me to angle my hands in correctly, a habit that I was able to take with me even when I started using other keyboards. Originally I kept my hands positioned like the photo below, but the shape of the Natural taught me to angle my fingers differently (pinky curled in and index finger extended out) so I could keep my wrists straight and still have my fingers rest in the home row position.
That said if you are looking for a comfortable keyboard and aren't ready to spend over US$100 for something mechanical I would recommend the Kinesis Freestyle; even though it's still a rubber-dome switch it's got a crisper response than most and allows for you to keep your forearms totally straight.
 The DSA (spherically-shaped cupped tops) keycap set that Massdrop offers doesn't include "homing bumps" for the keys under the index fingers, making it a bit tricky to get your bearing on the keyboard without looking down at your hands. I picked up a couple white caps with homing dots from Signature Plastics (matching black wasn't an option) and then went ahead and swapped the rest of the home-row with white as well along with a nice bright red Esc just for good measure. The only further hardware modification I have planned is changing out the switches under the pinky modifiers with Cherry MX brown switches, which require less force and should reduce pinky fatigue.
Update: I've replaced the switches on the outermost columns: the modifiers (shifts and ctrl next to the A key) are Cherry MX reds (lower-force and no tactile bump) since I don't feel like tactile response makes sense for modifiers. For the non-modifiers I'm using browns which are tactile and lower-force without being loud; the idea was to reduce strain on the weak pinky fingers. I don't feel like the browns make all that much of a difference, but I like the feel of having linear switches for modifiers. I've also replaced the modifiers under my thumbs with Cherry MX black switches, which are like the reds but with heavier springs since the thumb is the strongest finger.
 There have already been a number of further designs based on the Ergodox design, including the "Grand Piano" and this incredible string of prototypes culminating in a soon-to-be-kickstarted production run at http://keyboard.io.
 What's really eye-opening about putting a keyboard together is that you discover there's really no magic behind it. It's just a grid of switches wired into a microcontroller. Since microcontrollers don't have enough pins to detect each switch individually, there's a clever matrix wiring employed; each hand has six rows and seven columns where each row and column is wired to a pin. The microcontroller then scans each column by bringing all the column outputs except one low and then checking to see which row inputs are high. It can only technically scan one column at a time, but it's able to rotate through them so quickly that it's indistinguishable from simultaneous reads to a human. The same multiplexing approach is used for controlling an LED matrix with a limited number of pins. It's all there in the code for when you get curious.