What should the tire pressure be set to in my tires?

I need to go get my wheels balanced, and i'm gonna just have the rotate and air them up while they're at it... but i've heard a lot of people say that people over do it when they're just putting air in...
(don't remember who it was that said it, but i recently remember reading someone say "every time I have someone fill my tires I end up letting out about 12lbs of pressure" or something like that.)

So what should I have the tire pressure set to?

Stock GSR Rims, with generic all-season tires, if that makes a difference.

Thanks as usual.