Well now this is a difficult one!
I am a big fan of both parties, and find it really hard to narrow to just the one.
Biggie for his FREESTYLES - fuck the boys rocks them, his lyrics are seduced with rhymes.
2pac, for his ruff and rugged lyrics that just about fit every mood with a flavour of individual song.
But for me it will be 2pac, perhaps because he was a little more in quantity opposed to Biggie, i know it's about quality - after hearing more of pac, he's got to be the winner for me. I have heard every official album released by both parties, also own them too.