There's LOADS of tutorials and articles that would be of use. Even simple things like how to boot into safe mode, disable automatic restarts when there's a BSOD and so on would stop people having to repeat things over and over again. There's a whole load of linux ones that could be of use - setting up file servers, mythtv setups, that sort of thing.
I wrote one a while back on starting out with programming (stickied in the programming section.) Encouraging more of these would be good - it's one of the main reasons why I suggested a wiki where they could all be brought together and referenced with better organisation / accessibility.