Currently, it seems Skyrim has problems with crossfire scaling, and as a result I have to disable crossfire for it to run smooth. However, it runs pretty smooth with one 5870 at ultra with 8x AA, 16x AF. Worst case I get is around 45 fps. I noticed a problem right away when the game was running at 15 fps at the intro. Exited the game, turned off crossfire and it went up to 50 fps. This is dissapointing but hopefully ATI will release something to fix it. I have looked around for possible fixes and so far I haven't found anything, though I am going to try a beta driver and see how it works.
As far as crashing, I hadn't had problems for the first 12 hours of gameplay. However, starting earlier in the day I noticed a lot of crashing to desktops. I have confirmed this with my friends who are also experiencing crash issues. One said he didn't have problems on the first day he played, but as he progressed it got worse. This is similar to my experience. Often it crashes after fast traveling (for all of us), and it seems the instability occurs as you progress through a game.
I am very pleased however to see it run smoother than Oblivion while looking better as well. The story and setting is a lot better than Oblivion from what I can tell, though I do miss the RPG elements that Morrowind offered, but it doesn't surprise me that they wanted to move TES to a more "friendly" system. Besides the lack of crossfire support and the crashing here and there, I am enjoying the game.