Pragmatist, Mfkeleher, Fab4fan: Segovia and Parkening are good but...
As a concert guitarist myself, I can't afford too much high-end equipment but I know who can play the guitar, here are a few of my favorites in no order: David Russell, Assad Brothers, Tilman Hoppstock, Alvaro Pierri, David Starobin Timo Korhonen, Gruber & Maklar, lutenists Paul O'Dette & Nigel North, Stephan Schmidt, Franz Halasz, Denis Azabagic, Jorge Caballero (MHS). These are all really worth hunting down. There are soooo many great players, it's really a shame nobody's listening except other classical guitarists!