Wacom, wacom, wacom. Even their cheapest is pretty good. Personally i use an Intous which is one step up. Although the new entry level is as good as the former intous. But there isnt much else that really gives you usability in the same way. Sure, other brand may be dirt cheap, and thus value for the money, but most of the knock-offs are really just about unsuable once you get going and want it to just do its job.