I've been tasked with creating a fun and relaxing environment, one thing I know that I want is ergonomic mice and keyboards, others have suggested exercise balls and bands.
What is it that every programmer needs while working? What might not be necessary but would be nice to have anyway?
Besides a good computer, it would be the chair that is most important to me.
The ability to go to a quiet place to get work done. An office with a door works great for this.
(I'm not saying it always has to be a hermit cave, but there definitely times when a "do not disturb" needs to go up).
Wending machines, TT table. Fast internet connection with least number of blocked sites.
Big screens, even dual screens to have more at sight.
An area for team work (because it is often good to work in pairs) and private rooms for normal work.
All areas should have glass and windows to maximize sun light; this is vital for moral.
The walls should absorb noises and eliminate echo also.