2008. The year Fable 2 and Lost Odyssey (in the west) came out.

Even 2012 was pretty damn good, contrary to the narrative I so often hear (and which has never made sense to me) that 360's later life was disappointing.

Halo 4, Dishonoured, Max Payne 3, Black Ops II, Far Cry 3, Spec Ops: The Line, Forza Horizon, Sonic All Star Racing Transformed, all excellent.

My decision was made on a number of grounds 1. gained their console start /popularity on 360  2. became renowned franchises 3. 360 was the only place to play them on console 4. made 360 my main console for the first few years after PS3 came out.

Well, Metro and Alan Wake made their console debut on 360 and weren't available on PS3, while Bayonetta and Metro did go on to become franchises.

I mostly just base my picks on which games I thought were the best, regardless of exclusivity or sequels.

I know you play what you like, so do I and both of us don't need to have our selections validated by anyone but ourselves. The thread says 360's best year so my post was more skewed toward trying to look at the years in relation to the title, not just as a list of when each individuals favorite games came out although that plays a part after all we are gamers, by trying to gauge their historical impact by looking at how those releases affected the 360 going forward, obviously some more than others an example would be halo 3 releasing on the platform rating high on that scale and something like say Crackdown while helping the console being much lower, I would like to hear what games regardless of the release year you feel had the greatest impact on the 360 ecosystem. 

Gears of War was a big one, it was the system's first real killer app and set both a graphical and mechanical standard for the following generation. While I don't particularly like it GTA 4 was a megaton as well, Halo of course, plus Modern Warfare 1 & 2. My best year's still got to go to the one with the games I personally thought were the best though, but I've already gone over that at length haha

2007 was easily the best. It had great exclusives like Mass Effect, Bioshock, Halo 3, PGR4, Forza 2, Blue Dragon, Lost Planet, Ace Combat 6, Crackdown along with multiplatform games like The Orange Box, Cod4, Assassins creed, and Rock band which really made it a special year. 2010 would be my runner up.

Looking at the list from a 360 perspective it is a good year, but a lot of the narrative was was built around comparisons with PS3 and if you take away the multiplats you start to see the beginning of ( true or not) the Halo Forza Gear's box narrative.

The 360's later life had console exclusives outside of those too like Witcher 2, Alan Wake, Splinter Cell Conviction, Metro 2033, Fable III, Trails Evolution, Bastion, (at the time) etc.

I guess the fact some of these were on PC and games like Uncharted getting more hype feeds into the narrative that 360 was lacking in it's later years, but honestly as a 360 owner it was absolutely on fire from 2010-2012 and I could hardly have been happier with it.

The 360 has some solid exclusives through 2010-2012, but it was drowned out by Xbox's huge push with Kinect. 

Then we see Ps3 really pumping out the great exclusives during that same time so the narrative changed.