hi mary,
sorry i didn't see your post previously.
a couple of months ago i tried all the legally free bitmap editors i could find. and a few of them had some impressive tools, but they also lacked either ongoing development, or they had restrictions or bugs that bothered me.
so i tried the latest beta version of paint.net and that's the free app i've decided to stick with for the foreseeable future. i too can't get on with gimp's interface, no matter how much i tried to like it.
i've been using some of the cool plugins available for paint.net, a couple of which i've been beta testing and requesting features from the community devs.
and with a few extra steps to the workflow are now producing results almost as good as what i previous could do with paint shop pro.
also the main dev of paint.net is apparently intending to add in a lot of new features, although as he works on it part time (his day job is at microsoft if i remember correctly) the progress is slow, but it has a lot of potential over the next few years, in my opinion. and i like the clear and uncluttered interface, and how quickly it loads.
i recently worked on a 2d facial morph for a youtube video gamer that plays thief 4, where i morphed a photo manipulated image (done in paint.net) of the gamer into the face of garrett, the thief 4's protagonist. the actual morphing was done in winmorph (another free app) and video edited in blender.
for anyone who's interested in seeing the results, here's a link: