I havent played but will place highly :
COD5 [hopefully my xmas pressie]
farcry 2
have played:
no love for crysis:warhead/crysis wars? good singleplayer[but a bit short] a few new guns, stand alone, great multiplayer. Seems like a contender
fallout3. Enough said, you either love it or hate it[and even if you hate it, you can see why people would love it]
WOTLK. cant argue with sales. Massively popular, hundreds of hours of added play time, epic community, will consume your life. Good if you allready have WoW, if not stay away[especially if you have stopped playing recently]
C&C3/red alert3 both good games. RA3 was slightly overrated, for some reason C&C3 didnt seem to have great sales despite being imo a better game. Both are great though i would love to see one of them place in the top 10
GTAIV. Its a good game, maybe put it at about no.8
edit: GOW2? ok that game kind of sucked. For so much hype i didnt see what was so great about it. My friend bought 5 copies of it on release day so we could lan when our friends finished work, i played through the single player in about 8 hours. Yeah i had fun, and yeah the multiplayer was also good fun but it was nothing special. It just blends into the crowd of kinda fun games for me, Single player had no replay value, multiplayer had a few new modes but i cant see myself playing it for hours on end.