If your talking shred then Greg Howe's the man. He just seems to skip over the strings. Unlike Malmsteen, Vinnie Moore, Impelliteri etc he never went down that cheesy neo-classical route. Satch, though, probably is the best when it comes to having both chops AND tunes. I cant think of any rock player who's written so many cracking instrumental tunes that you can actually remember because the hooks are so catchy.

Country, folk and bluegrass players are almost always hugely impressive. If you want to hear some brilliant flatpicking I recommend Tony Rice, Beppe Gambetta, Dan Crary, David Grier and Steve Kaufman. For country style there's Albert Lee, Jerry Donahoe and a whole bunch of Nashville session players that you can hear on 'Nashville Guitars'. Some of the best acoustic fingerpickers I'd say are Leo Kottke, Peter Lang, Tommy Emmanuel, Adrian Legg and a newish guy on the block Peter Huttlinger.

If you had to pin me down on my all-time favourite I'd probably say Danny Gatton. He could play jazz, country, rockabilly, rock, you name it, equally brilliantly. If you love guitar you MUST check his stuff out. :D