I'm a hip hop snob; I don't Lil Wayne and I don't think Lady Gaga should even be called hip hop.
This list is in no particular order.
P.O.S. aka Stefon Alexander is a rapper from Minneapolis who can spit something like a million words in a minute (not really but he's pretty fast) His background is in punk rock and he doesn't try to hide it in his songs which have been known to contain fugazi samples. Socially aware and incredibly heavy, sometimes I wonder why nobody's ever heard of this guy.
Childish Gambino aka Donald Glover. Actor, Writer, Comedian, Donald Glover is the modern image of a renaissance man. He's released a few albums now -all for free- as well as his "I am just a rapper" mixtapes in which he raps over popular indie tunes. His wordplay is probably some of the best I've ever heard.
Mos Def has been around for a while and still never gets radio time, I don't understand.
Mickey Factz is what I think Kid Cudi wishes he could be. No, he doesn't have MGMT to prop him up on his tracks and he doesn't need them. His music favors synths over sampling and definitely has more of a "club" vibe to it but his lyrics are usually pretty personal unlike most hip hop. He might actually break out soon, I can never tell who record labels are going to turn into a megastar.
Cool Kids- a duo hailing from Chicago, they favor minimal beats and don't care that they stand out. They are probably two of the coolest cats alive.