the whole Halo Series (1, 2, 3, ODST and Wars), so many people seem to hate the games but i must admit im a big Halo fan, especially when i take the added depth of the books into account, a lot dismiss the Halo story as another 'typical, generic' human vs. aliens story, but its so much more refined than that and a lot of thought has been given to the UNSC, their weapons, their ships are made to be closer to modern armed forces than a futuristic fighting force.
Killzone II, nobody i know personally ever mentions this utter gem when asked about console games, don't think anyone really hates KZ2 but its became so forgotten in all this Call of Duty related rubbish which i think is a shame because it totally overshadows them in every quantifiable way, and graphically its the best game available for the current generation of machines. the Halo universe, told in a more cinematic way from the start in Killzone IIs engine might be my ultimate game, shame it'll never happen
GRAW and GRAWII, nobody i know has even played either of these games, they went straight for Call of Duty and are missing out on some real beauties, especially the second one which had me gripped from start to finish.