I prefer Game Revolution for my reviews. They're a smaller site, but I've found that they have the most honest reviews online. If they like a game, it's wworth checking out. They gave Skyrim an A, which for them is highly unusual.
GameTrailers typically has the best reviews that I've seen when it comes to getting the nuts & bolts of a game and whether or not it's worth a purchase. They're very thorough. Haven't tried Game Revolution, though.
IGN is solid, but sometimes their reviews seem to suffer from being rushed. I wasn't pleased to learn that Battlefield 3 on the PS3 had major issues that went wholly unreported on the site, such as connection issues, and the fact that microphone communication simply did not work
. Still doesn't. Now, nobody's even trying to use them anymore, so the game will likely be silent in perpetuity. It's a bit frustrating, and you'd think it'd come up in reviews, but not so much.
Still, it's good to hear that Skyrim is being well-received. I'm getting quite psyched.