For a rock album, there's no question I'd want John Bonham pounding the skins.
Keeping it rock, I'd still need guitar and vocals. If the singer played an instrument, I could get some keys in there, too.
Realistically, I don't think I'd want to be the fresh meat behind a big star guitarist, and get myself "produced" into a vapid, boring part in his shadow. So that crosses a few names off the list.
Clapton's used to working with Jack Bruce. He can sing, too. And he's a sound songwriter. Ok, he's in.
Now, who would fit in with those two?
All I can think of off hand is Gregg Allman. I think we could all lock in on a heavily blues-influenced rock and pull it off. Again, Gregg sings and writes, so this is a good thing.
I'll give John Paul Jones an honorable mention. The only reason he doesn't make my final three is because if I have two guys from the same band it looks more like a reunion than a new group. Obviously Jones could rock with Bonzo. And if he wanted to play bass on some tracks I could always move over to rhythm guitar. Or he could play guitar or mando. And he'd arrange some great strings and be a great addition to the songwriting. But, I'm not giving up Bonham, I'm not taking two from the same band, and so alas I have to pass on JPJ. (If he called me tomorrow for a collaboration I'd be on a plane before the phone was hung up.)
My final three:
John Bonham
Eric Clapton
Gregg Allman