I use GIMP to make mine. You'll hear all the photoshop guys say that it's the best, and I'll admit that there are more features and alot can be automated for you. But I do just as good if not bettter in some cases with my free GIMP software.
Thanks, yea on the services page they start getting pretty low and blending, but they're still readable.
The renderings above aren't 3d (didn't know if you were referring to them or what)