Well, the mods for Skyrim are already starting to roll in - the first one I've seen is a collaboration between Valve Software and Bethesda to bring a touch of Portal 2 to the game:
To celebrate the opening of the Steam Workshop for Skyrim, Valve and Bethesda have teamed up to bring you the Portal 2 Space Core mod, which will let the aggressively space-centric little robot tag along on your adventures in Tamriel.
Also, since Skyrim was the only major release of 2011 without Nolan North in it, you should consider this mod a patch to fix that problem. You can now feel free to include Skyrim in the "Nolan North" section of your video game library, which is to say, your video game library.
Check it out on the Steam Community site. Great to see two companies that really get the PC teaming up to do something neat to help promote modding.
scuzzy points out there's a video showcasing the mod, which you can now see below!