In reply to The Lemming:
Well, I never realised that what I regarded as the theme to The Hitchhikers Guide to the Galaxy was an Eagles' song
However, in terms of great "guitar" tunes there are several others...
Steve Vai's "Passion And Warfare" is a guitarist's classic instrumental album from 1990, and is till spoken of in "classic" terms nowadays as influential and a demonstration of guitar noise making and technique par excellence
http://en.wikipedia.org/wiki/Passion_and_warfare
There is almost certainly either live or straight from the album clips on youtube of every song on that album.
For starters, you might want to look at "for the love of god"
I also tried to listen to Satriani, but I just don't get on with him.