Alanis Morissette is probably the one I'm most attracted to, but I had to pick Avril Lavigne, by virtue of sentimentality. Avril is a bit of a personal legend for me, not necessarily one of my favorite artists but definitely one of my most important milestones; providing me both with my first pop guilty pleasure after I had become a rock purist, and gifting me my very first bona fide pop album when the tattered walls of my little isolationist music bunker began to crumble and let the wide light of the music world inside.
So uh... yeah. I don't even care how the date would go or anything. Merely to be on a date with Avril Lavigne would be so far up on the novelty meter that I would probably slip into a coma. *shrug*
Besides, Avril is decently beautiful. Particularly before she went blonde 'cause now she basically looks like a Britney clone. :/ But back in the day she was relatively smokin'.
Out of anybody, I'd have to pick somebody who I'm vibing on more at present. Probably Hayley Williams or maybe even Ke$ha just because I love her music so much.