One act I want to see in the afterlife is Queen. I came close to seeing them whilst Freddie Mercury was alive, and passed up on the chance. I really regret it now.
David Bowie is also very high on my list. Again, I never quite got round to seeing him and should have.
I have mixed thoughts about the prospect of seeing Michael Jackson in the afterlife, for the same reason I had mixed thoughts on seeing him in concert whilst he was alive. Nothing to do with his music (which I mostly love) but more to do with how much his fans terrify me.
Oh, also Amy Winehouse and JImi Hendrix please.