Universe 2.0 Sideswipe and Sunstreaker get my vote for Best Of 2008. I love the fact that we get two different-looking figures out of essentially the same mold.
My runner up would probably be Binaltech Bluestreak. I really like the Subaru mold, and the blue they used is just perfect. Not owning ALT or BT Smokescreen makes the figure that much better.
The best surprise of the year was, of course, Henkei Thundercracker.