I'd have to agree with longhair about Lightnin'. He floats my boat. Love to hear him talk just about as much as I love to hear him sing ("Whooo....'Xcuse me miss, for me askin' you this, but who may your good man be...")....and don't get me started on his playing....
John Lee Hooker deserves honorable mention.....and one of my favorites that doesn't get mentioned much (I've noticed) here in this forum: Jimmy Reed.
More recently and electrically speaking: Chuck Berry - not normally known for it - could do a decent job on a blues number. "No Money Down," "Things That I Used To Do," "In The Wee Wee Hours," and (appropriate for the holidays) "Merry Christmas Baby" are more bluesy than rock 'n' roll, Chuck Berry-wise.
Stevie Ray Vaughn and (of course) Hendrix could always give the blues an electrifying workout.