I have been using books much more this last year, especially from the college library and I joined the public library as well recently. Plenty of useful information to be found in those.

I have never really used an encyclopedia though, other than my Britanica 98 CD and Microsoft Encarta 98 back when I didn't really use the internet much.

I also find Wikipedia very useful. I agree with what some people say about how you should always try and back it up with other sites and not use it on its own. It is however a good place to start looking for something and contains lots of information.