In the current gen, the Wii probably leads in this category of "mis-hyped" games, typically in support of the notion that the platform was/would become more relevant in terms of third party support. Or maybe that should be third party support in the form of hardware selling exclusives.
The Conduit, as already mentioned is the first that comes to mind. The mislead was in regards to the visuals from a tech standpoint, but also as new exclusive IP that would show all those doubters that the Wii can have and will have more compelling third party exclusives. A lot of the same pundits either wrote the game off post release, or fell silent. Only a small minority carried on about how good the game was.
Madworld was a big exclusive title that was supposed to show how the platform was viable for "adult" titles and shake the family console only image. Post release, most pundits wrote it off or fell silent again.
Red Steel 2, not hugely hyped, but supposedly another title that would prove the viability of third party WIi exclusives as well as demonstrate the significance of Motion Plus, and another title that quietly came and went to a mediocre response at best.
Final Fantasy XIII on the Xbox 360 in hindsight was one of the biggest bombshells (closing announcement for MS at E3 '09) that so many got so pumped up and worked over by yet in reality upon release, really didn't change much of anything.
I'd bring up Haze again for the PS3 as a "Halo killer" but it's not the first game to be falsely hyped by being compared to the cultural phenomenon that is Halo; just one of the worst.
I can't think of any post Crysis/Crysis Warhead games being hyped as AAA VGA card upgrade worthy PC titles, but if there were, they would probably belong on this list.