Not too many legitimate responses here, so I'll step up to the challenge...
Mainstream rap is garbage, but there is some fantastic hip-hop that does not get the recognition that it deserves. Real music, not brainless drivel.
A few of the best:
-The Roots- Water
A mind-blowing live show. I've seen them twice and want to see them many many more times. This song is for one, brilliantly written, talking about resisting the temptations of drug use in the music industry. Two, it has one of the best bass lines in any song ever.
-Atmosphere- Always Coming Back Home to You
It's criminal that Atmosphere doesn't get a bigger recognition. This Minneapolis M.C. is one of the smartest, funniest, and most personal artists currently active. This is his best serious song.
-Atmosphere- National Disgrace
I've got to include the less serious stuff by him as well. This track is funny as hell, talking about celebrity infamy.
-Jurassic 5 - Sum of Us
Chali 2na's deep bass is one of the most identifiable and memorable voices in hip-hop.
-KRS-One - Step Into a World
"I'm not saying I'm number one, uh, sorry I lied. I'm number one, two, three, four, and five." One of dozens of awesome lines in this song.
-A Tribe Called Quest - Like it Like That
Super chill hip-hop that just rolls off the tongue. Cool as hell. My ears can't get enough.
-Afroman - Crazy Rap
Funny, filthy song. Big guilty pleasure of mine. "I met this woman from Japan, never made love with an African, I fucked her once, I fucked her twice, I ate that pussy like shrimp fried rice."