Don't know if you prefer acoustic or what, but you've already gotten some fine suggestions there. Gotta agree with practically anything Fahey, Kottke, Hedges(RIP), Cooder, some selected Bromberg (if you're OK w/ those vocals ;~), etc. Maybe check out Hawaiian Slack-key or Calcutta Slide, Doc Watson, Grisman/Garcia, Adrian Legg, Neal Schon, Atkins and Knofler. And the various samplers (Narada, Windham Hill Guitar Sampler or Touch, etc.) are consistently interesting and very good. I think my bro-in-law had something called Acoustic Heart(? - I guess that's the title) that was really decent. Shoot - there's just gazillions of good stuff (and never enough time).
And Zappa. Do we go Electric here? Dang - that's a whole 'nother book. Maybe it's time to start your "guitar CD trust fund", 'cause you could need one...
