GIMP's too cool to have the layer toolbox option by the regular one, apparantly.
That would be because it is not a toolbox

The toolbox is still a one-of-a-kind thing, and it.. you know, contains tools, rather than
a list of layers, or a color selection dialog, etc.. Those are dockables.
I generally only use GIMP or the like when doing photo manipulation/optimization, since it produces such a jittery stroke.
This is substantially changed in more recent versions of GIMP, thanks to Alexia Death. It's not perfect, but the current stroke smoothing in 2.7 produces fairly smooth results which I find generally satisfactory.
As for recommendations: I'll second RuneFox's MyPaint recommendation: if you want to just draw, and forget all the complications, it has exactly the right level of simplicity.
For pixel art, Grafx2 (or Pro Motion if you have the $). For animation, GIMP + GIMP-GAP (I know you want to avoid GIMP, but this is honestly by far and away the most powerful animation suite I've ever used.)
EDIT:
Also, MyPaint is just the most helpful ever for quick shading.[Lighten/Darken actions, which alter the current painting color and work even during a paint stroke]