I entered the web world with Paint Shop Pro and never got around to learning much Photoshop. I made all the graphics for Stroke of Genius with Paint Shop Pro.
As the years have progressed, PSP has become ever more powerful with layers and vectors just like Photoshop. In fact, in many ways, Paint Shop Pro is more user friendly and guess what? The price is around $70-80 compared to maybe $500 for Photoshop.
Photoshop was long the darling of the print world and was originally only available for the Mac. Photoshop from the start was more web-oriented. For serious design of print pieces, Photoshop would still be the way to go. But, for web design and other graphics applications it's well worth considering.
One note, in the current version PSP 7, there is a slight problem in font rendering. In smaller faces, the spacing between characters is often uneven. It's correctable by hand, but can be a pain. They are looking to solve the problem. It's still a great product!
Click image to order from Amazon.
http://forum.portraitartist.com/images/psp.jpg