The main hub of all things SuperCollider.
A good source of community-edited SuperCollider docs.
The SuperCollider Book
Highly recommended. There are excerpt chapters on the site so you can get a taste for it.
Musician, performer and programmer extraordinaire. He has a lot of music informatics-related SuperCollider extensions on his site, including the forever useful bbcut library.
Jan Trützschler von Falkenstein
You know what, *all* of these people are musicians, performers and programmers extraordinaire. It's a SuperCollider thing. There are lots of examples of Jan's work here.
James develops the very thorough and very useful dewdrop_lib in SuperCollider.
Lance J. Putnam
Lots of very useful extensions!
Plenty of music here from the very prolific Sergio Lugue.
Dan does a lot of machine listening/learning work. He is also a very active livecoder.
SuperCollider was written by James McCartney over a period of many years, and is now an open source (GPL) project maintained and developed by various people.
SuperCollider Users mailing list
A very very very useful mailing list - essential if you want to get serious with SuperCollider.
Julio is an audiovisual composer and performer. He has contributed to the SuperCollider Book.
Another genius musician, performer and programmer extraordinaire - with a visual bent as well. Lots of very good code here.
Thor Magnusson (IXI Software)
Lots of really nice UI stuff here.
Till has done a lot of work on Tangible Auditory Interfaces and sonification classes in SuperCollider.
Josh has contributed loads of plugins and extensions to the SuperCollider project. On this site you can listen to some of the music he has created with SuperCollider.
Simon is an artist - a lot of his installation work is documented here.