Well, since Fallout 3 is so similar to Oblivion I interpret that they would have included Oblivion there if Bethesda never made a Fallout. But just like ICO can't be there cos Shadow of Colossi already is, they had to ditch Oblivion in favor of Fallout 3.
I'm happy they didn't put World of Warcraft or a Call of Duty or even a Halo there. Actually they could have put another Blizz game like Diablo 2 but they didn't. Props to IGN.
So, a good list!