I didn't initially respond to the recent experimental hip-hop thread, because I thought most of the responses were pretty right-on (Co Flow, Ice, Wordsound, etc.)
However, after getting the new DJ Vadim - USSR - Life From the Other Side" today ($6.00 after coupon from bn.com BTW, sweet...), I'm reminded that Vadim's stuff could decently fall in the "experimental" realm. I've seen his name a bit on this list in the past, but I just want to throw it out again for new-comers. "Life From The Other Side" is essentially a collaboration album; almost every track features guests MC's. Favorite tracks: "The Terrorist" w/ Moshun Man (Kool Keith collaborator) and "Your Revolution" with Sarah Jones, in which she disses the whole "Jiggy" phenomena. There's also a EL-P track for all you Co Flow heads. Who would have thunk that some of the dopest Hip-hop would come from Russia?
Also, I just wanted to mention how nice Scorn instrumentals sound as instrumentations to acappella hip-hop tracks. I've had really good results with Ras Kass and Gravediggaz...