A-.
Best game of my year, hands down, but it can't get an A+ because the interface is unreliable, the audio engine has stupid limitations that Fallout 3 and Oblivion didn't, and gaining a level is unsatisfying/boring.
In detail:
clicking on a category closes the menu ~50% of the time. It acts as I expect 50% of the time. There's no obvious way for me to entirely restructure my character without favoriting EVERYTHING, or entering the menu more than once. After 80-ish hours, I'm STILL not sure when I need to use wasd, and when they do not work at all. and why is my journal in a totally different menu than my map?
Who decided that 24-bit, 96KHz shouldn't work, when it works fine in previous games? More to the point, does the PC QA team all use headsets instead of trying with an X-Fi and 5.1s? It's hardly an uncommon setup these days. Us PC gamers aren't known for frugality. I'd be less annoyed if I were accustomed to playing BGS games through headset only (Skyrim is currently in a class with, in my collection, only Prototype: games that don't understand 96KHz output), but it's a downgrade in compatibility.
As for levels being unsatisfying, it's subjective. In my case, gaining a level is still too fast in the 40s. It's just not rewarding when I ask myself "didn't I just get one a few minutes ago?". Then, when I do get one, I just can't seem to care. The stat increases just don't change the outcome of a combat often enough to be a reward. If I would have lived, I still live. If I would have died, I'm still going to die. I wind up making an absurd "rule" just to help me "choose". Then I get to pick a perk. According to the numbers, I even usually do so. That said, I have 6 or 7 stored up, and little to no motivation to use them. Getting my butt handed to me isn't even enough to motivate me to add 20% to block or heavy armor.
All of that said, I put down money for a massive world with a lot of adventuring to do, and the potential of the province of SKyrim to do it in. They delivered that to a slightly generous A+ or very stingy A in my book. If I come off sounding a bit negative overall, it's just because the negatives are... more personal... than the positives. But... just to mention a positive, I got to watch a giant one-shot a heavily mailed Orc clear off my screen. It took me minutes to find the body, no less. Never did see it come down, but it apparently did. I also made someone on the other side of the country smile while I was listening to Sheogorath. Probably because I was laughing my butt off. So there's a lot of good things, but they're almost impossible to relate without spoilers.