Well if you are talking about the real classics, i.e. the early blues artists then it has to be the likes of Robert Johnson, Son House, Lowell Fulsom and many others or you could go for T Bone Walker, Muddy Waters, B B King, Albert King, Freddie King and Billy Jean King ....I was joking about the last one. I would say rather than religiously working your way through them that you perhaps get a traditional blues compilation or two and see if it speaks to you whilst taking in the atmosphere.