I'm probably stuck back a year or two, but I've loved
GTA4
All the Orange Box, still playing TF2 regularly
The Club
WOW:WOTLK
and the plethora of free web games still being churned out full of originality and playability.
To me, the only downside of GTA was the badgering from 'friends' could get a bit much, but you can put them all on 'pause' in the options.
WOW and TF2 have one of the same good points in common, they're both great games, unless you're an elitist, and can't stand the idea of average players enjoying the game and having a chance against you.
WOW does seem to be the 'whipping boy' of gamers nowadays, its blamed as the cause of everything bad about the industry (ok after EA), but to me, WOTLK revitalised a game getting a little stale and really added a hell of a lot of stuff for a lousy £18. (yes yes, and the monthly fee). No it's not perfect, but I get more entertainment for my £9 a month than I would from many £40 releases.
The evolution of Steam too, the weekend offers are excellent, and allow people to get hold of older games for reasonable prices, I seem to remember GTA1,2,3,VC,and SA combined for $40, and recently Half Life 1 for 99 cents. They're also hosting some of the better mods now, supporting the community. I know they're doing all this to make more money, they're a business, but just goes to show there's more than one route to turning a buck *cough*EA*cough*.