Didn't see a thread like this and there are quite a few good musical collaborations out there worthy of being cataloged, so let's do it. Remixes,
mashups, and covers don't count, sorry.
To kick things off, a couple of my personal favorites:
Okay it would take too long for me to link youtube videos, but i like:
Santana and Eric Clapton - The Calling
Santana and Chad Kroeger - Into the Night
Santana and Kirk Hammett - Trinity
Santana and Steve Tyler - Just Feel Better
Santana and Will i am - Somebody
Michael Jackson and pretty much anybody else. I really like the songs he did with Slash, especially Give in to Me and the collaboration with Santana,
Whatever Happens. Also an unreleased song with Freddie Mercury called There must be more to life than this.
Sting and Sheryl Crow - Always on your side
Slash and Roger Daltry - No More Mr Nice Guy
Stevie Ray Vaughan and Santana - Traffic Jam
Johnny Cash and U2 - The Wanderer
Bob Dylan and Johnny Cash - Girl from the North Country
If someone wants to take the Rap collaborations please feel free to do so. My knowledge of the genre is admittedly limited. If it came out after
Ludacris' third album, I haven't heard of it.