You would really have had to play the second game when it was in its hay day to get why its so anticipated by so many. Suffice to say that the diablo series defined or I guess redefined depending on how you wana look at it an entire genre.
Mass Effect 3 for sure.
Dragon Age 2, though I'll wait for reviews.
And I'm really hoping TESV doesn't suck. Read an interview recently with Todd Howard where he stated (something to the effect of) if there was one element he would like to bring back into TES series, it would be a more robust sense of culture. As that's one of the main elements Oblivion lacked, I'm hopeful. I'm also ready for it to be a dumbed down suckfest, too. I'm keeping my fingers crossed.
I think if HL2: Ep3 was confirmed for 2011, it would be on top of a lot of PC gamers lists. Overall, I think Source engine games have been some of the most fun I've had on my PC in the last decade, and I'd love to see the end of HL2, if only so that the HL3 speculation can start in earnest.