Clark would be great for Obama.
I would love to see Lieberman on the McCain ticket vs a Clark/Obama match up.
Unfortunately as much as McCain does like to reach accross the aisle (unlike his opponent) he may alienate his base too much with Lieberman.
I doubt Obama will pick Clark, He has too much negative influence and too strong a personality which would detract from BHO's image.
Eaither way it will be one hell of an election.