I also have fiio e07k
Its for home use but i really cant to spent too much money, only if its very needed
I have the M80's, they sound great with rock to me (Fiio E09 and E07)...don't know about rap much, but from my reading of other posts on this site I'd say they'd be ok (have a search, there's probably loads of posts about this...).
I have the M100's and currently listening to Lil Wayne's Dedication 3 mixtape with no amp. I mean, they AREN'T Beats, so you're not going to have the extra pushed up bassline, but it's absolutely there and sounds fantastic. On some songs it's downright quaking.
Hooked up to me Fiio e11, it turns CRAZY bassy with the boost on. No idea about the e07k but I'd wager you'd get an even better response.
Good lord. Marked down from $300 to $80 on Amazon? That's... less than encouraging, haha.