Not sure if this was about games released in the last decade, but I'm listing the ones I played this decade.
Top 5
Metal Gear Solid series - the interactivity of these games blew me away (MGS and Sons of Liberty mainly)
Gran Turismo Series - love cars, tuning them, and racing them.. one of the best simulators
Battlefield 2/2142 - spent countless hours playing these two.. mostly BF2
Freelancer/Disco - getting close to being the most time spent on a game ever
Rockband series - I play guitar and drums, so this was a ground breaking game.. being able to jam with friends