I was looking through some of my old bookmarks in order to clean out the ones I don't need anymore, and I discovered a few gems that I thought others might find useful or interesting. I'm sure others have some good ones too, so let's see'em.
Here are my top 5 (in no particular order):
http://www.nationmaster.com/index.php
Contains countless statistics on countries and geographic regions. You can find almost any kind of information about any country.
http://www.freeinfosociety.com/
Tonnes of obscure, interesting, and sometimes usefull information. From cooking recipes, to street fighting guides.
http://www.timeanddate.com/
Has currency converters, and clocks for pretty much every major centre in the world.
http://altervistas.com/
Good for a laugh once in a while. It's a catalogue of bizarre and humourous websites. Click on "Random Site".
http://www.allmusic.com/
I've been introduced to a lot of good music through this site. You can search for practically any band, and it will list comparable genres and artists. It's fun to just surf around until you find something interesting.