Heh, rather early summer I'd say.
I use Cosmigo's ProMotion, and the features I normally use (apart from the basic ones like save -as many different file types-, open new document, shortcuts etc) are , uhmm... Brushes (esp, 1 and 2x2 pixel brushes), Paint bucket, Eye dropper, Selection tool (Box Selection or whatever it is called), Lasso tool, Mirror, Zoom, Rotate (Free rotating without randomly generated AA), undo and redo, Stencil, Shrink, Remove unused colors, Brush container (along with save/load brush), Preview Window, Palette box, Palette management overall, Zoom grid, Transparent color box, the whole animation menu (Add frame, remove frame, etc etc), Resize frame, Create text brush, and... uhmm I guess I missed something, but that's all I could think of right now.
Features I can't live with are: brushes, paint bucket, eye dropper, lasso tool, undo/redo, preview window, brush container, rotate, mirror, transparency, animation, resize frame, zoom, zoom grid, etc. But if I were considering a different program, it should have additional/better features than the one I'm currently using, otherwise it wouldn't be much of a wise move, but anyway.
Additional functionality I would like probably would be some autosaving feature (which you could edit the settings for it to save automatically every x minutes/hours), alpha blending, and maybe layers (though I never needed them, but I guess they could come in handy). And of course, stuff like cooking for me, cleaning my place, go shopping, would be neat, but doesn't necessarily have to be on a pixel program

, but if you manage to, I'm sold!
oh and I'm on Windows XP