The problem with Gimpshop is that it hasn’t been updated in a long time. The next version of the Gimp will have a better interface (including a single window variety), but, for right now, that’s the most annoying part of it.
Although I’m generally against pirated software, I’m getting close to reinstalling a pirated copy Photoshop CS2 that I unwittingly bought from eBay for my Photoshop class.
Oh, and the Gimp doesn’t have shape tools or any vector abilities, but I find I can use Inkscape, the open source answer to Adobe Illustrator. Other than a deficient bitmap trace tool, it’s pretty good.