1. dual monitors, at least 21",
2. Comfortable high-back, leather chair - not an aerolon or other mesh-back imitator.
3. Nice set of monitor speakers.
4. Good keyboard - not too hard to press keys (slows me down). I prefer wired to wireless, as maybe it's just my cheap wireless equipment but sometimes it doesn't seem as responsive as wired.
5. Decent optical mouse - almost anything nowadays seems fine - I do remember back in the day having to open up the mouse and clean the crap off the innards.
6. Good printer within a few feet.
7. Good coffee making system nearby. By this I mean a setup with REAL milk, coffee that I can purchase and make rather than put up with company big pots.
8. Good lighting. I have a window, blinds, and 3 lamps in my room. Right now I don't need any lights - at night i might need 1 or 2, but from a particular direction. Sometimes I need the blinds to cut glare.
9. Well-stocked fridge. Doesn't need to be nearby - it IS good to get up and stretch your legs once in a while :)
10. Plants - for calming influence, and another excuse to get up and stretch your legs (they need misting).
11. A window, and natural light. Much less depressing. Also another good reason to stretch your legs (and back) - take a look outside once in a while.
12. Decent computer. Specs are meaningless, since they change all the time. Basically I go for a high-end system, selling at a medium system range cause it's refurbished from a big box store. People return systems to big box stores all the time, because of trivial reasons (they don't like the color, got it as a gift, etc. etc. - now they are used, basically all the cording has to be re-shrinkwrapped, but nothing is wrong with the system).
13. Headphones - for when the roommates are trying to sleep.
14. No one checking up on me :)
15. Telephone nearby. I have skype and cell.