The Goal: Use votes to rank nominated sites. The first answer to reach 100+ votes will be accepted.

Please answer following these 5 simple rules:

1. ONE SITE per answer.
2. Link to each page if nominating a "series" of resources on a SITE.
3. No "offline" books. Only online resources (tutorials, API references, blogs, screencasts, etc).
4. Don't add "subjective" details/notes in your answer. Add them as a comment to the answer.
5. Don't post duplicates. If your favourite is already listed Up Vote It!

Example Answer:

Site Name
http://www.example.com

Example Answer (site with a series of resources):

Site Name
http://www.example.com

Series Name A
http://www.example.com/video/a/1
http://www.example.com/video/a/2

Series Name B
http://www.example.com/video/b/1