Since I'm a HUGE hip-hop head...I'd have to say it would be Lupe Fiasco. I love lyricism in hip-hop.
Other favorites would probably be: Eminem, Slaughterhouse (group), CYNE (group), Kendrick Lamar, & Ab-Soul.
What about you guys? Hip-Hop, Rock, Country, whatever you'r favorite genre of music is...lets hear some favorite artists!