Ratatat and Jay-Z. Twice. The first track features a slick, funky bass line overlayed by slick, muted guitar and organ(ic) synthisizer. The second track features Notorious B.I.G. What more can I say? Biggy continues to kick ass as a mash-up legend (though notably, his label would rather that not be happening).
Ratatat Remixes Vol. 1 and Vol. 2 are fantastic albums, and I highly encourage enthusiasts of mash-ups and remixes to explore their hip-hoptastic landscape. You might not find it surprising that an instrumental group could easily mix together with spoken word, but Ratatat worked to develop original soundtracks to these rhymes -- it's readily apparent that they weren't just layered on top of each other.