I'm typically openminded about music in the sense that I won't knock someone for what they like just because its not something I like or listen to a lot. I'm of the thought that every genre has its quality and has its... well... trash. for instance, i really do like rap/hip hop but will be the first to say that i think lil wayne is horrible.
i just say that because you say metal and rap are enemies. i don't listen to metal, but i can respect it.
Nas, Biggie, Wu Tang... all very nice. you really can't beat the classics and those are some classic type artists that you mention.
i'm somewhere in between the underground and mainstream in what i like. i like mainstream artists that stay true to form and don't make nonsense, or underground guys on their way up.
artists i like include Eminem, Lupe Fiasco, Common, Talib Kweli, Jay-Z, Nas, TuPac, B.o.B, Wale, and J. Cole.