Some personal favorites:
SRV - the man (RIP)
Johnny Winter - blues, rock, slide, resonator wild man
Billy Gibbons - Hot, Blue and Righteous - tasty Texas blues back in the day before the beard
Freddie King - I'm going down, down, down, down, down
Duane Allman - blue when he wanted to (and RIP)
Some newer guys:
Chris Thomas King (from New Orleans)
Keb Mo (Delta heritage but a wide variety of sounds)
Jonny Lang (plays a tele)