Oblivion is definitely one of my all time favorite games (I'm still getting into Morrowind when I have the time, but I'm already loving it), and TES games in general because what I love about them is how they engross me even outside the gameworld. The Lore and community for TES is
beyond phenomenal, I find myself thinking about the stories that aren't even a part of the games all the time. But there are other games that will forever be a part of my heart and soul, several Star Wars games, (another fictional universe I'm positively infatuated with) particularly the Jedi Knight games, KOTOR, and Battlefronts I and II (I'd be just as hyped to a next installment for any of these games (that is well done) as I am for Skyrim. Probably) and of course I was brought into the world of Consoles by Halo, yet another story/fictional world I love. (You can kind of see a trend as to what draws me to the games I favor). Games like COD and whatnot are great and all, I love the competitive aspect to them, but I never touch the campaigns. They just don't have the great stories that really play my heartstrings with the melodious choruses of heaven.
Edit: I suppose I should add Runescape to that list even though it's been a year or two since I really played it, it's kind of my guilty pleasure, and I go back every now and then when I'm bored. While I've put in hundreds of hours into TES, I've put in over 100
days into Runescape. As in bordering 3000 hours. (yes, three-thousand)