Favourite Collaborations?

What would you say are your favourite collaborations? It can be from any time period, genre. etc. ;) My personal favourite would be Miles Davis and John Lee Hooker. Both completely Polar opposites with Genre somehow make this Odd coupling into Gold...Check it out! ;)

Bank Robbery

I'm Coming to Town

Hmmm, I have a fair few, collabs can have some pretty interesting results :P

Dirt (feat. Aesop Rock) by Tobacco

Pinky's Dream (feat. Karen O) by David Lynch

My Machines (feat. Gary Numan) by Battles

My Secret Friend (feat. Imogen Heap) by IAMX

Fall Creek Boys Choir (feat. Bon Iver) by James Blake

Are some of my favs, though I've got many many more that I enjoy :P