+1 for the Aeron. you can get a used one on eBay or CL for less than $500. replacements parts are easy to come by.
personally, i have (well, had. the ex gf has taken it hostage) a loaded herman miller ambi. its a very nice chair as well.
-sj
lol! everytime i go to the thrift store or flea market i have to press the keys on the stack of old keyboards. so far, i've only found one, but it was made for IBM POS terminals and doesn't work with mac/pc. the one i'm using at the moment came from dad's stash of archaic e-junk. :D
that...