I like a number of them.
Randy Rhoads
Kirk Hammett
http://www.youtube.com/watch?v=5SRtwpiMkDU
Zakk Wylde
Mark Tremonti
Steve Vai
http://www.youtube.com/watch?v=8Iih9gSPlKs&feature=related
http://www.youtube.com/watch?v=2XCsjITUFdM
Page
http://www.youtube.com/watch?v=VnqpOFcBiMM
http://www.youtube.com/watch?v=DGKOir9KJ4E
http://www.youtube.com/watch?v=f8zE-hEkILs&feature=related
http://www.youtube.com/watch?v=9Vwk3-a0k7c&feature=related
http://www.youtube.com/watch?v=nJNHoY8T7G8&feature=related
http://www.youtube.com/watch?v=qYS732zyYfU
There's quite a few more but I don't want to be doing this forever. I don't really like guitarists for riffs, but more or less for sound, speed and technique. I also like a good shredding solo.