Aesop Rock.
Prof is fun,
Eminem (sorry boys, he's good. He used ot be better, but its whatevs)
Busdriver
Can Ox
El-P
Watsky
Jarv
RA the Rugged Man
Talib Kwali
Mos Def
etc.
A lot of the hiphop I see is pretty pathetic actually. The 'fad' is the fast rap stuff, but most of its done terribly. The flow kinda sounds cool, until you realize every "fast" rapper sounds almost exactly the same and the nature of the delivery is such that it actually excludes a lot of what you can say. If you compare verses between rapper with that style, you'll see what I mean.
For an interesting example of fast done well, check out Jarv, Mac Lethal, etc. Its the staccato delivery done correctly, and not obnoxious repetition and over-used dumb shit.
I try not to be a snob when it comes to hiphop, and I can enjoy fun music (see Prof) but when an artist makes most of his music about how good at rap he is, and that's the basis for MOST of his public/heavy rotation stuff, he needs to actually BE good, and thats kinda few and far between.
I owned a recording studio when I was younger. Almost 20yrs ago now actually (ugh) and we were primarily a hiphop studio, and all my own stuff and what i worked on personally was all hiphop. Three albums (I'll give anyone here a thumbs up if youve heard anything by Soul Sleep), a 6 month self-funded tour, headline and opening act for the Hiphop festival in Cinci a million years ago, along with similar at the Nashville New Music Conference... The end result is I consider myself mediocre and a rapper has to be AT LEAST better than me to be worth listening to, because shit knows I am not worth listening to, and I can blow most of this shit out of the water. Or could, a long time ago. God only knows how bad my breath control has gotten.