I had some sort of an error while installing the game from a disc ("STEAM servers are too busy to handle your request! Try again later."). Now it says the game is installed, but it's updating and says that the update is going to take 9 hours. Steam's properties thing says that the local files take 5740 Mb, but I can only find 270 Mb worth of Skyrim files in the Steam folder.
Anyway, could someone with more knowledge about stuff tell me if there really is a huge 9 hour download patch and it's normal that there's only 270 Mb stuff in the Steam folder, or should I delete the files and try to install from the disc again?
It might be doing what some other Steam tethered games do - install only a few steam cache type files and then do the full install via Steam. I know that is what happened when I bought and installed Dawn of War II a few years ago [though in that case it installed ~5GB and downloaded another 5GB - which was basically overwriting the disc install :/].
For many Steam games on disk the disk is just to have something physical, the main install tends to be via the Steam client no matter what [a bad idea imo - especially in situations like this when steam servers are over loaded]. You could try changing your download server location [Steam Settings, Download/Cloud tab] to something either closer or a little further away to see if the load is less.