A tough one. Skyrim is out due to Bethesda's terrible performance with Oblivion. Witcher was a breath of fresh air when it came out and CD Projekt is looking to take the sequel in a great direction. But Bioware is Bioware, and I really dig the sword-staff they've got the protagonist wielding in all the trailers.
I'm going to have to give it to Bioware and Dragon Age 2, for brand loyalty (they have yet to disappoint), followed closely by Witcher 2, with Mass Effect 3 in third place.
Skyrim is on the "keep an eye on it" list, since Beth did do better with Fallout 3, and I like a lot of what I heard about the changes in Skyrim. However, Bioware games are a sure thing, so Skyrim just can't compare when it comes to pre-release hype, at least for me.