Metroid Other M, was in my opinion the biggest surprise of E3 last year. The fact that Team Ninja and Nintendo have teamed up for one of gamings most beloved franchises was a real shocker. As the guy said, just the mere fact that it is those two, that seem to have totally different mindsets on gaming have teamed up is really something.
Also the expansion of the Metroid Universe is something that every single Metroid fan has been waiting for. I have personally scanned and read every single log in all three Metroid Primes, just because it is one of my favorite gaming universes. I think the number 1 on the list was fair.