Michaels would be a good craft store to check. While your there, you may want to pickup one of these:
http://www.solder-tools.com/prod_img..._heat_tool.jpg
They're perfect for heatshrink tubing.
As far as hobbyshops go, it depends on your area, HobbyTown is one national franchise. They carrying products for static and remote control models, etc. If you're big into painting, you might want to consider an inexpensive airbrush so you can custom mix your own colors. The nice thing about airbrushes is the larger the subject, less expensive the tools needs to be.