I'm now seriously considering moving to GIMP because my Photoshop 4.0 is reaching the end of its usefulness. Becoming more and more unstable, even with fresh re-install. I think it's because of the endless Windows XP updates. And most likely it won't work when I am finally forced to move to Vista.
Most importantly, GIMP now has the healing tool! Something which PS 4.0 does not have.