Don't limit your options!

http://www.refdesk.com/

Oh, yeah, I've had refdesk bookmarked for a couple of years now. It's a great quick resource, but I do wish they'd quit rearranging it! I find it easy to remember that something was, for ex., on the right-hand side about 2/3 of the way down; but if I have to search and actually read as I search all over, it takes much longer to find what I'm looking for.