I have a very, very old PhotoImpact which is really easy to use. I use it for banners, logos and the like. They have a new one that came out, probably around 40 bucks, which is now Corel PhotoImpact. (You may be able to find an old version for 10-20 bucks?)
I mainly use PSP-Corel Paint Shop Pro X-1. Think I paid 80 bucks...Believe you can now find it for around 40-50 bucks)
Lots of free programs on the net. One I just download and trying out is called
PhotoFiltre.
Free Editors:
Paint.net
PhotoScape
VCW Vicmans-(This was my first editor) Photo Editor (Download site has bad reputation?)
Ultimate Paint
Picasa...Photo organizer with some editing capabilities