Hmm, tough question 
For me... triple monitors, a high-end Mac Pro w/ Apple Cinema Displays. An exercise ball at my desk so I can switch between that and a chair so I can maintain great posture (I have horrible posture).
The desk should be quality, nothing cheesy or flimsy, big surface area.
For the actual office...
Pool table and air hockey are a must. Unlimited supply of purified water. Unlimited supply of grass-fed beef jerky that was made with no sugar, sugar substitutes, or MSG. Also an endless supply of meats and cheeses.
There should be a nice 60" big screen somewhere w/ xbox/PS3 and cable. Tied into Netflix.
Ability for each employee to customize their work environment, paint the floor, desk, etc... personalize, no matter what they want.