For those into some bad ass, mellow guitar music...
Buckethead has a massive discography and his music is all over the place. Some of it is fast/hard, some really weird/funky, and some is mellow (what I like obviously).
I only wish I had found his music sooner, as it is some of the best I have ever heard.
Here is a look all the good, mellow tracks I have found so far.