Joey -

You'll be hard pressed to find an image editor better than good old Photoshop. Although aquiring Photoshop legally is not a cheap thing to do, there's ways around that. Although I certainly would not recommend doing that if you intend on making money by using the software. Photoshop, like any software, has a kind of steep learning curve, but once you learn it, there's nothing you can't do.

For a cheaper alternative, check into Paint Shop Pro.