I love Deep Purple and Rainbow - the most brilliant Guitar work ever.
I make my own brainwave sync tracks with the Mind WorkStation (new product from the guys who made Neuro-programmer 2).
I listen to classical.
But mostly rock and "classical" metal from those two bands. I enjoy hearing the interplay of different chords, hearing the structure, feeling the emotion of the playing.
Did you know that Smoke on the Water is based on Beethoven's 5th Symphony inversed?
I also listen to ragas from famous Indian Classical composers, like Ustad Zakir Hussain, Valiyat Khan, Ravi Shankar, etc. I enjoy listening to vituosity

.