I'm also considering the artsy side of things too. I'm narrowing down the basics of the character design to something I like. However the question I've been pondering recently is whether I should go for a hand-drawn look from a raster based art program (i.e. GIMP), or the more "smooth" look from a vector art program (Inkscape).
All of the concept art listed below is the raster hand-drawn variety; it's reasonably quick to draw, but suffers a bit from slightly wobbly lines and is a pain to edit mistakes.
Here's a vector image I drew with Inkscape last year. It's a bit rough due to my unfamiliarity with the program, and is a bit different from the style I'll be aiming for, but is close enough for comparison purposes. Vector graphics are smoother and curvier (it's a lot easier distorted circles!), and I don't have to worry about scale issues with the raw images. Fixing mistakes is easier too for those times when I just can't seem to draw a line the right way; all you need to do is move a few notes. I guess it will also be easier to do small changes for animation with the vector approach too.
The downsides are that I'm still not that proficient in vector graphics with Inkscape (although this can be fixed with practice), and I'm not that sure quick the whole process will be compared to the raster approach (although this year now my computer is a bit more powerful I hope performance issues won't as big a problem).
I guess I need to try drawing a few detailed vector based images to experiment with the process, so I'll get something done over the weekend.