Well... since you do not say where in the world you are, I will have to assume it's warm enough all year round to work in a garage.

I think whatever you use as a bench, make sure it is sturdy and not extremely sensitive to vibration (wood is better than metal).

The other thing to consider is that standing for long periods on concrete can play he!! on your back... I bought one of those rubber anti-fatigue mats for my darkroom... it's a good thing!

Drawers are nice! You always need shelves, drawers or whatever. You could even make one of the drawers light-tight and use if like a paper safe while you are working.

If you get a stool (as opposed to a chair) you could actually have it both ways... standing until you get tired, then sitting for a while. Just make sure you don't wonk the bench while you are exposing paper... makes for sore knees and ruined prints! haha

Hope this helps a wee bit!