Ranking the best-selling branded drugs in the world is a bit like gathering the most popular kids in high school together in one room. The usual suspects are always there (in this case, that means Lipitor, Plavix, Seroquel, Effexor XR, et al.) until they graduate--or in this case, go off patent. Then they're suddenly missing from the chosen few. So take a close look at this year's crowd, ranked using IMS Health's 2008 sales figures. In some cases, it'll be your last chance. Slideshow