the guitarist i've seen the most live, is rab mccullough.. he was the first person i saw play guitar with his teeth, play behind his head and do slide guitar with a mop lol
im also a fan of paul pilot... loved his bowed guitar playing and of course, he's pretty good on the banjo.
and foy vance is awesome on acoustic guitar
Rab...
http://www.youtube.com/watch?v=9tJC50rFIK0