Skyrim.
It just looks like a much, much better game and (despite bethesda trying this a little with Oblivion) it doesnt sound like its being dumbed down too much to try and snare a casual audience. In fact, it sounds like certain things have been done to specifically make the game more rewarding for hardcore players.
Bioware lately just seems to have an insatiable urge to dumb the living fuck out of everything it makes, so it stands no chance.
As much as I thought I would adore the trilogy when Mass Effect first came out, Im current looking forward to Skyrim more there too. Im expecting the dumbed down shooter nature of ME not to have been fixed, and probably even have competative multiplayer shoved in to be even more like Gears.