I love stackoverflow, its great for finding answers for questions you need answered right away! Or its good to be able to help others get over annoying speed bumps.
Code Review ( http://codereview.stackexchange.com/ ) is a lot more interesting in terms of actually becoming a better programmer. You get to reflect on other peoples code, offer up alternative ways of coding, and see other peoples alternatives.
The only problem at the moment is there’s just not quite enough code to review!