So this post is ridiculously self-indulgent; you've been warned. I've mostly written it out here for my future self to look back on in a mix of amusement and embarassment. It's just a write-up of the tools I use daily in the style of the Q&As at usesthis.com.
Update: I had a real interview posted on usesthis.com in 2012.
I use a Thinkpad X200s primarily. It's hard to find a machine that's acceptably light (2.4 lbs/1.1 kg) but still has a decent resolution; most "small" laptops these days have a vertical resolution no greater than my phone, which would be embarrassing for me to use. The Thinkpad has the best keyboard of any laptop; I appreciate the crisp response. It also has an integrated trackpoint, which is nice in that you can move the pointer without taking your hands off the home row, but I try to avoid it as much as possible. I'm much more productive when using 100% keyboard commands. Sometimes I'll just pluck the trackpoint out entirely just to make sure I'm not using it without thinking.
I work from coffee shops frequently since I have a remote job, but when I'm in my code lab I use a standing desk with an external 23-inch monitor. I rotate the monitor to portrait orientation when I'm not remote pairing with tmux. I have a recliner next to the desk onto which I fall back to for a couple hours out of the day. While I'm standing I wear what has been affectionately termed "keyboard pants". It's a Kinesis Freestyle with kneepads attached. The kneepads are worn significantly above the knee—the idea is to allow myself to type in as neutral of a position as possible. My arms are relaxed in a downward position, and my wrists are totally straight. It takes some getting used to, but from an RSI perspective it's quite beneficial. It also just feels great not to be sitting all day.
I keep a Nexus One phone in my pocket. As far as I know it's the only major phone currently available that's designed to be rootable by the end user, and hence the only phone I am comfortable purchasing. As a nice bonus it also happens to be one of the best phones available, though it seems absurd to call it a phone. I hardly make any actual voice calls on it, though when I do it's VOIP calling through Sipdroid. I have CyanogenMod installed, which has a really nice auto-tether over USB.
I start with a boring old Ubuntu GNOME install. To my embarrassment I actually even use metacity, the default window manager. My secret sauce is devilspie, which is a rules engine for window placement and behaviour. I fullscreen and undecorate all my commonly-used programs and have certain programs only show up on a given virtual desktop. It's flexible enough to trick people into thinking I use a real WM. My other main desktop-level customization is xbindkeys, a little app that embeds a Scheme interpreter to configure bindings. This is nice because it decouples them from the window manager. The only part of GNOME I use on a regular basis is the panel. I like having CPU/network/memory graphs available so I can tell when my machine is hard at work. The panel wifi tool is pretty handy too.
Apart from that it's Emacs, Emacs, and Emacs. I am mostly able to maintain the illusion that Emacs is the only program I actually interact with regularly. I generally have four or five instances running at once which is uncommon; most Emacs users keep single instances with uptimes in the weeks range. I use this as a namespacing technique to keep real work separated from play/chat/mail. My staple modes are magit, clojure-mode, slime, paredit, org-mode, and erc. I used to waver between jabber.el or elim and leaving the embrace of Emacs for something like Pidgin, which was not pleasant at all. But now I'm pretty settled on bitlbee, which allows you to connect to your IM accounts via an IRC client.
I have all my Emacs config (accumulated over years of obsessive tweaking) bundled up as the Emacs Starter Kit. Lots of other developers use this as a base off which to build or just to steal ideas from, which I love. (It's a little funny to get bug reports for your own dotfiles.) I try to save all my other config in git as well in order to make it easy for me to get up and running quickly on a new machine.
The other key to maintaining the Emacs-all-the-time illusion
is Conkeror. Emacs doesn't have
a modern web browser in it yet, so this is an attempt to trick
Mozilla Xulrunner into thinking it's Emacs. Apart from being
implemented in JS instead of lisp, it's a very good
approximation. The buffer switcher features completion that's far
better than anything I've used in a mainstream browser, and its
mouseless browsing support is excellent. It's also very stable as
long as you don't have any garbage plugins like Adobe Flash
Its only flaw is being based on Gecko rather than
Webkit. I've experimented a bit with mouseless extensions for
Chromium, but the extension mechanism in that browser is crippled
in comparison to what's possible in Mozilla, so while the speed
boost was nice, this ended up being very frustrating in
Update: I recant my complaints regarding the speed of Gecko in light of the latest Mozilla nightlies; they are absolutely zippy. I am no longer tempted to go back to Chromium. You can use Firefox rather than Xulrunner to launch Conkeror by doing bin/firefox -app ~/src/conkeror/application.ini.
Unfortunately I need to use skype for work. While I've been pretty impressed with its ability to use a very limited amount of bandwidth, it's quite unstable, and its UI is very awkward. Since it's not free software there's very little hope of this improving soon. The one thing that eases this pain is the skype plugin for gnome-do. It allows calls to be initiated from the keyboard. While I am a fan of the ideas behind gnome-do, this is the only thing I use it for since in general Emacs does a better job at the kinds of things it does.
I really wish I could buy a modern laptop with a 4:3 aspect ratio. I find the loss of vertical space in widescreens very annoying for anything other than watching movies. Apart from that the Thinkpad X200s is nearly everything I want in a laptop. In a perfect world I would have a battery with the weight of a 4-cell and the capacity of a 9-cell. Half the weight of my laptop is the battery.
I recently switched to using gmail in the browser, and while it's decent for everyday mail it is markedly inferior to gnus for mailing lists. I'm only using it because it syncs with my phone, and setting up offlineimap to work with gnus and gmail sounds like a lot of work. This is definitely the least-satisfying part of an all-Emacs setup, at least if you want to read mail on a mobile device.
I imagine if they ever get the senseboard working it will be a pretty sweet innovation. I could also use a HUD for my phone for when I'm in the car. Or possibly on my sunglasses for when I'm just walking around; you know... I'm not picky.