The other day I was thinking to myself, "You know, I'm glad I don't have a widescreen display, because I already waste a lot of horizontal space. Vertical space is much more valuable." A few pokes to my xorg.conf produced this:
If you're using X, the trick is to add the line
Option "Rotate" "CW" to the relevant device section. Not sure about other OSes; I've heard you can do it in Windows if you buy a special Samsung monitor. Thanks to AaronP from #xorg on freenode for pointing me in the right direction.