This is an interesting article comparing different CPUs running Skyrim and other games. Looks like the i5-2400 is the absolute minimum for running Skyrim at 1080P if you want decent FPS. I'd like to see this test with the beta patch.

http://www.tomshardware.com/reviews/gaming-fx-pentium-apu-benchmark,3120.html

They're using a 1.2 version of Skyrim. Testing is invalidated for comparison to current Skyrim performance since the 1.4 specifically does *so bloody much* to ease up the CPU needs of the game.

Looks like ultra would be fine with an i3. Could also turn the AA and AF down before anything else. Interesting how much the cpu matters with this game.

I'm actually using the i5-2105 and in most cases it works fine at 1080P but the interior mist and light sources reduce my FPS to the twenties compared to fifties outside. The beta has helped but it seems to have made the delta of minimum and maximum FPS larger in my case.

Meh, my system is below and I have had absolutely no issues whatsoever in 120+ h of play (I'm done, only waiting for the pathc to get stone #24 in the embassy to finish the last quest). I have no clue at what FPS I'm running but it doesn't lag nor slow down. Both cores run at ~100% while playing though. Playing at 1920x1080 on ultra for all except shadows at high.

Well, just by turning shadows down to high, or tweaking them manually you get a better looking (at least for manual tweaks) AND faster Skyrim where the CPU won't matter much most of the time.
Also no info on where they tested it (please correct me if I'm wrong).

But yes, SB is a very good processor generation - had I bought my current rig half a year later i would probably have bought one myself.