Audifeil,
regarding the no rap thing, if you listen to most of Dr.Dre's production work with Eminim, the slight musical nuances that build up in the background you would be very impressed. I suggest the Marshal Matthews LP to start, listen to whats going on behind the vocals.
I can also suggest you try The Nappy Roots catalog, very musical.
Your missing out on a lot of great stuff, Beastie Boys etc but hey, it's your record collection, not mine.