I definitely agree with your 2006 pick the camera angle made me hate the game but I believe you are wrong about Killzone..! How many times do you hear about Killzone now a days...! The only reason why it is brought up is to rag on the fact that they showed a CG trailer that many think is un realistic to accomplish...!
Most Over-Rated 2006 = Gears of War
Most Over-Rated 2007 = Not sure but if I had to guess at it then I would say Killzone just because people hype it up too much.