LaLaLa-Jay Z, he may not be that great of a rapper, but the bass is crazy. Some of his other songs have good bass too. I dont know if it was mentioned or not, but some old Nas has good bass.
Definitely look to the rap of the late 80s/early 90s. For some reason, the music was mixed differently, it probably had a lot to do with the quality of mixers and speakers but I find the true "old school" rap hits way harder than new stuff.
dint read the whole thread so i dont know if theyve been said: I'm Assuming your looking for Hip Hop to play on your new Sub haha king kong, By Jibbs (Deep Bass) Bombs over Baghdad, By Outkast (mad fast bass) Make it Rain, By Fat Joe Its like That, Run DMC (oldschool shit haha)