Well, actually...I pretty much agree with this list.
Think about it. Half-Life 2 and Halo, both great FPS' that gathered huge popularity and drew more people into gaming.
Wii fit and Wii sports. Wii Sports being the definitive title that came with the Wii, so pretty much its the game that introduced everyone to motion controls. Wii Sports because for a lot of people its revolutionised how they keep fit. Though a lot of you will argue that the latter is not really a game.
Bejewelled; POPcaps crazy addictive puzzle game. Again, a lot of you will brush this off as "casual", but a lot of people really love this game, and play it tons.
Guitar Hero was the first game to use the funny little guitar thing, and heck, it was really fun. While it doesn't boast the track list of the sequels, the original is there because again, it revolutionised how we look at gaming. Its not all about joypads and single player, suddenly it was really fun to set up little plastic guitar controllers at parties and rock out with your friends.
Same again with the Sims, first in the series, very unique at the time and incredibly popular.
GTA 3 redefined the 3d sandbox genre, or invented it depending on who you talk to. And it was really good.
WoW sorta speaks for itself. 11 million subs.
The only one I can't place is Super Mario Galaxy, but I've never played it.
Hardly any of these titles appeared in the latter half of 'the noughties', but that doesn't mean they didn't have a huge impact on gaming. Bigger than some of your more modern titles.