The folks at Contagious have put together this - Download mostcontagious2006.pdf - list of the most Contagious of 2006. A thorough review from design to retail and marketing - not that there's much difference anymore.
While you're brushing up on 2006, the forcasts for 2007 have begun. The folks at PSFK are using YouTube here to collect community submitted weigh ins via video of trends for the coming year. Just tag as directed