I'd settle for #8.

David Mizner offers Ten Reasons To Vote For Edwards. OK, nine. Who's counting. Any one will do…

By Voting for Edwards, you…

Reward and advance progressivism.

Pull the race to the left.

Preserve the possibility of (an unlikely) victory.

Make Edwards kingmaker (or platform editor).

Reject the self-fulfilling nominating system driven by polls, pundits, and money.

Sign on to a movement

Increase the likelihood of a meaningful convention, which would be good for Democrats.

Piss off the establishment.

Do something good for your soul.

Come Up with Your Own Reason (I ran out of time but didn't want to change the title)

He elaborates here.