The top, and highly recommended, program is Photoshop CS3 but it sells for $624.99 even on Amazon! PaintShop Pro Photo X2 is considered by many to be pretty much equal and sells for $72.00 on Amazon (I've seen it cheaper elsewhere--around $50.00 sometimes).
There are tons of excellent books about Photoshop. Good information about PaintShop Pro is hard to find—there is a lot of information but it is mostly about older versions and few tell you how to do the basics.
Both programs can do incredible work; both programs are rather complex to use. There are other programs that are pretty good but I don't think any of them have all the features for advanced graphics that these do.
Of course if you are thinking about video and the like that is a whole different story.
My vote is for PhotoShop but as James said it's a bit pricey. You can try GIMP http://www.gimp.org/ It's really more for manipulation of existing images but I do believe you can do some authoring.
Thanks guys. I think you might be talking about Illustrator cs3. Photoshop only edits pictures (I think?).
No PhotoShop is also used for creating web graphics, banners, etc. I use them all the time for that. It also comes bundled with a program called "Image Ready" that allows you to do animation.
Graphics
Matthew
If....
Linear Mode
