I can honestly say that over the years I've watched loads of game trailers and Skyrims was only the second one that impressed me, most do nothing for me including Oblivions.
I totally agree with you. It's really rare that a trailer comes out that both really excites me, and represents the game well. For instance, the Halo 3 announcement trailer gave me chills the first time I saw it. It had barely anything to do with the actual game, but just the combination of thrilling music and excellent visuals was enough to get my blood pumping. Skyrim's gameplay trailer gets me super excited, but it actually seems like it's a pretty good representation of the game. Also, the threat of Dragons is cooler than the threat of Patrick Stewart dying in Oblivion (which we all knew was inevitable, he never survives long in games).
And yeah, the Star Wars Old Republic trailer is excellent. I've tried getting into WoW a few times, but it's never really stuck with me. I'm definitely trying The Old Republic, hopefully I'll enjoy it enough to get to the endgame content.