I personally don't rate Paint.NET, A good one for linux (with KDE) is KolourPaint, it is like MS paint, but supports larger palettes and transparency.
* Hint Hint* The iso lines are still busted. The idiots are using splines as lines.
I tried this last night and foumd that it cannot make proper isometric lines. I used the line tool and as soon as it made a line with a slope of 1/2 the line went compleatly crazy. Anyone else notice this?
Unfortunately Paint.net which seemed to be a fully replacement of a nasty Microsoft program, actually is based almost entirely on Microsoft framework libraries which is as nasty as the original Microsoft paint it pretends to be a replacement of. Paint.net is just an unacceptable nasty program...!