I'll echo 90% of the responses in the thread and say that mainstream is crap. I'm a fan of Kanye though, I thought his newest CD was brilliant. The songs that really got me hooked were the ones that didn't become singles though (Good Morning and Big Brother in particular).

I'm also (like 90% of the other posters here) a huge fan of the underground scene. Talib Kweli and The Cool Kids are both near the top of my list. I mean, Black Mags by The Cool Kids has to be one of the most intoxicating songs of the past few years for me.