Ms Image composer has been my main tool for about 10 years, but I also use:
Bylight 20/20
Image Pro
Impact Pro v10
PhotoShop L4
LivePix
and an Irfan Viewer w/PS plugins
Preview (most basic of things)
Inkscape
The Gimp
Seashore
Photoshop (4 on my laptop, cs3 when on the other comp)
Pixen
I used to use photoshop more, back when 4 was new... And when I still drew on paper. I've switched to vector art when I draw, as it scales to any size infinitely.