I have two favourites, Bayonetta and Enslaved: Odyssey to the West.
Not sure when Bayonetta came out in the UK, but I only recently got it. Enslaved was released in October, but I only got it last month.
Oblivion is my third favourite, and that's been out for quite a while now. Got it/played it almost as soon as it came out. Although Bayonetta and Enslaved are relatively new discoveries of mine, I just KNOW that they're going to be with me for years to come.
Sorry...that wasn't exactly just one favourite *blush*
EDIT: Bayonetta came out in Jan 2010, Oblivion came out in March (I think?) of 2006...does that sound right? Can't find conclusive evidence online...maybe I'm looking in the wrong place
