[iversonian]

My answer is: the hand whose sum of EV-gains when his decision (fold/call) changes is the greatest.

Say, J7o. Suppose that is the median hand (?) and a folding hand against an unknown random hand. The difference in EV from folding (EV=0) and calling when the opponent turns out to have a weaker hand than J7o, is gained by the information. When it turns out he has a better hand than J7o, that information did us no good, we would have folded anyway.

I think the answer is found by finding the hand for which, summing the abs(EV) versus opponent's hand for which decision changes x the % of time opponent will have said hand, is the maximum. If it a hand that would call with, it would be the EV against opp hands that beat you x % he has that hand. If it's one you'd fold, SUM EV against hands you beat x % he has hand.

So which one is it? Dunno. But I think it's probably a hand like K2. Pretty close to even against a random hand It's a slight favorite, as most hands have 2 cards in between K-2. It dominates only a few hands, and when it's dominated, it's drawing slimmer than most (unlike say 98, which can make straights and has overcards to many pairs). Because the hand characterized by its small edge against the many hands that are slightly worse and the large, um, un-edge against the better hands, my vote is for K2o. Sorry, no numbers.

Geez, I just checked the thread and David posted his K2o comment. Gonna post this anyway.