here are some others that my photographer mate uses when he doesn't require the full photoshop bells and whistles: he recommended them to me- they are oriented more towards photography. These are all free, because as we all know, photographers can be tight gits (I suspect its because they have no money left after they have bought photoshop

Photoscape
FXPhoto
Picasa
PhotoPosPro
Gimp
GimpShop (Gimp mod with a photoshop "feel" to it, probably aimed at photoshop users)
I have tried these and they are all handy ones to have tucked away on the hard drive. Photoscape has a lot of other functions I dont use like RAW converters, screen capture, animated gifs and batch editing.
apart from Gimp they seem to be trying to be jack of all trades but masters of just one or two things.
My l "most used" are Paint Shop Pro, and Paint.Net. Photoshop was always a bit overwhelming for me. Too much stuff.