C. F. Martin & Co.
The Martin Co. has made classic American acoustic guitars since 1833. Easily the most respected manufacturer of quality guitars in the world and the most popular among musicians despite rise of independent luthiers.

Gibson Guitars
Look through a catalogue of Gibson's acoustic guitars for a grittier, rootsier, bluesier sound than most folkies use these days. Site loads slowly, but moving cursor over model names changes the catalog pics.

Gore Music
Makers of nylon coated Elixer strings. Strong supporters of the folk scene.

MacDonald, Scott
Long Island based luthier repairs and builds custom guitars for Lucinda Williams and others. Yes, that was Lucinda with one of Scott's resonators on SNL.

Pearce, J. - Strings
This instrumentalist/performer has designed distinctive guitar strings that many musicians swear by. No mean feat.

Taylor Guitars
Founded twenty years ago, Taylor is probably the most popular of the up and coming manufacturers of high end guitars. They have brilliance and bass, but soul is harder to come by.