Best Networking Sites to Use

I wanted to get together a collection of networking sites recruiters and sourcers could use to link and find candidates. I'm only aware of 10 of them worth yours and my time. Here they are in no particular order:

LinkedIn - LinkedIn is the best networking site with over 19 million professionals registered.
Spoke - Spoke gives you access to over 35 million candidates from over 900,000 companies. Basically you give a candidate or hiring manager's info and you get one in return of your choosing.
MySpace - Believe it or not this site has alot of places to find candidates with different groups to join and a handy search you can use to target them.
Facebook - This is a good site to find people as well and has a huge following of people signed up.
Orkut - Orkut is google's networking site and another good one to use when sourcing candidates.
Fast Pitch - I really like the design and style of this site. The only downfall about it is that you can't really do much without upgrading to a paying membership.
Ecademy - A smaller site then some of these giants with only about 150,000 candidates, but who knows might have the one that you need! They do offer advantages to you for every 10people you invite too.
Ryze - Another good site that alot of people haven't heard of with about 500,000 members.
Konnects - This site allows you to connect with many different groups/communities that allow you to access the right people you need.
Naymz - This site allows you to build a page and gain an online reputation. Its a cool site and could be helpful for some of you.