1. Functional desk
2. Comfortable chair
3. Tea, coffee, and other refreshment facilities
4. General cleanliness
5. Temperature control
6. Small meeting rooms -- Has become more important as open-plan offices have more and more become standard.
7. Restroom privacy
8. Functional printing, copying and scanning equipment
9. Natural light (not the cheap beer)
10. Nearby restaurant or canteen
(Inc.)