..for true bass experience I use HiSound Wooduo 2, which are very nice, once you get proper fit. They have amazingly huge amounts of precise deep bass and work great with dubstep and rock (never tried them for hip hop since I don't listen to that genre). Their mids are not too recessed and their treble is supersweet, good enough that I don't mind listening to baroque trumpet works with them. Bad point is that Wooduo 2 has (for my ears) huge ports, so proper fit is difficult, it took me forever to find tips that were comfortable and gave good seal.
..my other recommendation would be Klipsch x10, when you have proper fit they have oodles of bass while also managing to sound flat across the board (ie, non recessed mids and treble). Very precise, without being harsh and/or fatiguing - they sound good with any genre of music. They are also by far the most comfortable universal IEMs that I have ever tried - supersmall and light.Unfortunately their cable relief splits easily (though I glued it back without any problem).