I've been getting back into watercolor and discovering my love of it (due to my inability to not be anal about things I do on the computer). My previous art teacher got me hooked on these watercolors, and, while a bit expensive, they are *so* worth every penny. And the tubes they come in are about twice the size of the kind you'd usually find, so you get a lot for your money.
http://www.danielsmith.com/ Aside from your usual colors, they have a lot made from different sorts of materials, some making nice granulation effects, change color depending on how the light hits them, and so on. They're *very* fun.
However, the nice thing about them is their triad deals, which pair three colors in a theme together for a deal. They keep changing around and getting sold out, so it's a good way to splurge on some colors you may have not bothered with otherwise.