I like just about all the collaborations the Chemical Brothers have done, though my least favorite would probably have to be The Boxer. But I love the Charlatans, I just wasn't a big fan of Burgess' flasetto on the song (which he sort of adopted for the Charlatans album Wonderland and used on The Chems' Boxer).
I liked Noel Gallagher's work with the Chems, but I never got into Oasis. It's not that I don't like them, I do - just never dove head first.
I was a fan of The Verve (as in, they were one of my favorite bands when they were together) so I about had heart failure when I found out the mighty Richard Ashcroft was going to be working with the Chems. The Test is one of my favorite collaborations.
Beth Orton can do no wrong, really. Honorary Chemical Sister. I never got into her solo stuff, but everything she's done with the Chems have been excellent.
Trespassers William - I should really give them more than a listen here or there. I really liked what I've heard of them so far, they remind me of The Cowboy Junkies in a way. Hold Tight London still gives me goosebumps when I hear it and I think Anna Lynne's voice is gorgeous.
New Order - I'm pretty much where satur8 is on this one. Welcome to the old!! haha. Same with Primal Scream...
I have plans on checking out Willie Mason and giving a serious ear to his music. What I've heard from him so far has been really really good.
There's more, but I haven't moved through all the threads and posts that popped up over the weekend so I'll wrap it up...