GIMP,
Jasc Paint Shop Pro (demo: free 30-day trial),
Photoline,
Ulead PhotoImpact (demo)
Images Generator 8.01 (nice for banners, elements and so on)

These are really nice programs, some demos, but if you like them, ofcourse you can buy them and get even more features.
Jasc Paint Shop Pro is my standard editing program (I use 7.0, eventhough it's aged....who cares;))