It all depends on what kind of blues you are looking for?. Personally speaking I like late 1960s & 1970s blues/rock from guys like Johnny Winter & Rory Gallagher although a guy with an electric guitar playing some slide blues is good to hear as well that takes you back to the crossroads at midnight down in Mississippi.I'm just now seriously getting into the blues. So from my neophyte point of view, it all depends on what sort of music you like listening to. Me, I think the sub-genre that I like is called electric blues? I've gotta have a good beat, some cool blues guitar, and some passionate singing.
The most obvious one is BB King. I've always liked what I heard, but just recently got a greatest hits compilation. Same goes for Buddy Guy. I think these are the best introductions because you can get a sampling of the slower stuff and the higher energy pieces.