I skipped the Police for Modest Mouse, and am glad I did.
As for the two mentioned groups, I would love to see Jack Johnson again, and V Fest would be a great setting for him. As for the Foo Fighters, I do not really listen to them or like them, and would probally be at the second stage while they played, but they are a popular band, and a lot of people would probally come out for them.
My votes:
My Morning Jacket
Interpol
nine inch nails
Underworld
Daft Punk