There's a wonderful researcher working in the UK by the name of Jane Hart who compiles a number of Top Ten lists on everyone's favorite learning tools. With so many new and amazing ways to find and share knowledge out there today, narrowing to 10 is a tough task, but I'm taking it on just to spread word on my favorites and link you to the consensus page that Jane hosts.
Colleen's Top Ten Learning Tools for 2009
Wikepedia - What do you need to know? The world may have an answer
Jing - easy screen and action capture
Flip Video - sometimes, it's about the hardware.
GoogleDocs - collaboration across time, space, applications
Blogger.com - Learning through reflection and inviting comment
Ning - creating quick communty sites for social learning
Twitter - and related apps (tweetchat.com, search.twitter.com) for all things micro-bloggable
SlideShare - takes the tech glitches out of presenting and stores for anytime retrieval
IBM's Many Eyes - Visualizing data in new and intuitive ways
If you haven't explored any of these tools yet, take some time. I've used them all in my teaching, learning to find, share, make sense of or collaborate in the knowledge realm. And some are just plain fun to use. If you have others, favorites, can't live withouts...send them on to Jane or me.