In mist go to your contract and run the winningProposal() function. This computes the winning proposal taking all previous votes into account.
/// @dev Computes the winning proposal taking all
/// previous votes into account.
function winningProposal() constant
        returns (uint winningProposal)
{
    uint winningVoteCount = 0;
    for (uint p = 0; p < proposals.length; p++) {
        if (proposals[p].voteCount > winningVoteCount) {
            winningVoteCount = proposals[p].voteCount;
            winningProposal = p;
        }
    }
}
It will return the ID of the proposal with the most votes. See proposals struct:
// This is a type for a single proposal.
struct Proposal
{
    bytes32 name;   // short name (up to 32 bytes)
    uint voteCount; // number of accumulated votes
}