I use PixelNhance from Caffeine Software, but I keep GIMP on my computer just in case I ever have the courage to try and make something of myself. I've seen SeaShore floating around, and saw something called GIMPShop that was supposed to be GIMP with with a Photoshop interface. I suppose Photoshop Elements won't do?
Caffeine "has suspended operation," but they link to downloads of their software, so I assume it is free to try/use. They also provide TIFFany, which looks like a more powerful program, but like GIMP, I'm still a bit nervous about playing with it.