Lotta hate for mainstream hip hop but I dunno why. Drake has good lyrics, a fast-paced flow, witty punchlines and most importantly raps about his life instead of trying to be someone he's not. I'll admit I wasn't sure what to think of him after Thank Me Later (was a good collection of songs but not a good album if that makes sense) but he made a classic with Take Care and earned my respect. This past two year run he's had has been fucking amazing and if you love hip-hop and R&B you should be able to appreciate that.
Kendrick Lamar, J. Cole, ASAP Rocky are all hot too and make good songs, not just good verses. Out of all those ASAP is probably my favorite just because he's so different. I liked K Dot and J. Cole right away because they're pretty straightforward: good lyrics, good beats, good songs and anyone who likes 90s hip-hop will love them. ASAP though took me a while to really wrap my head around his style. I didn't get why this guy was calling himself the pretty motherfucker and rapping about fashion over old-school UGK beats when he's from Harlem but after I listened to a bunch of his songs it just clicked and now I bump that shit all day.
As far as rappers who I like to just spit a 16 but don't really need to hear a whole song from, I like Danny Brown, Yelawolf, Action Bronson, Big KRIT and ScHoolboy Q. Q actually makes some pretty good songs so it's probably not fair to put him here but I don't think he's on the level of ASAP/Cole/KDot yet either.
Edit: Forgot to mention Childish Gambino. I'd put him on the same level as Rocky and Cole. He doesn't have a major label album yet but if he ever puts one out he's gonna be a superstar. Til then, he's the mixtape king.