I would love some suggestions on great acoustic...

Antonio Forcione's "Tears of Joy" and "Meet Me in London".

Manuel Barrueco--Albeniz/Granados, Vox LP also available in a 3 CD VOX set (I think it's called something like "400 years of Classical Guitar)

FOLK/COUNTRY/BLUEGRASS:

Doc Watson; Doc and Merle Watson
Ricky Scaggs
David Grissman(madoline)
Ry Cooder -- Paris-Texas soundtrack.

JAZZ:

+1 to John/Paco/Al
Bireli Lagrene
Egberto Gismonti mostly found on ECM label is new age/jazz solo guitarist.
Vlatko Stefanovsky/Miroslav Tadik acoustic albums -- EXTREAMLY ADDICTIVE! Once downloaded, I couldn't stop listening for weeks.
Filip Catherine(who once trained Larry Corryel)
Jim Hall/Pat Metneny acoustic duo

CLASSICAL:

Certainly John Williams!
+1 to Manuel Barrueco; -- They are veterans both
today's classical guitar maestros:
Rolan Dyens;
Jason Vieaux;
Ana Vidovic.

EXPERIMENTAL AND MODERN CLASSICAL:

Goran Ivanovic/Andreas Kapsalis acoustic duo. Goran also released his solo album as well.
California Guitar Trio also Robert Fripp String Quintet 3+2 with California Guitar Trio and Tony Levin(stick bass, fender bass).

Well can't beat Chet Atkins for flowing and melodic. Lots of great recordings out there that sound better than ever on a good modern hifi.

Also +++ for most anything by Doc Watson.

Lots there alone to keep one busy for along time.

Bruce Cockburn - Speechless