Depends on what you want to do. For games, Illustrator wont be really useful (except mayb for creating splines later sed in 3d) because it does not produce bitmap images but vector arts. So it is good for typography, illustration and design. Of course, you could still make some stuff with it for games but you''ll definately need a PAINT package (for bitmap).

IMHO photoshop is the best (i dont like paint shop pro but many pple asy its good...) and I also use Painter alot... especially for concept art and hand-made textures...

Biere et punk