Vote for who you want to be the next GM. Try to factor in the likelihood of the mets actually getting the person to come work for this team. I.e. if you think the mets have zero chance of getting the person you want to vote for, you should probably vote for someone else - but that's up to you.
See James' thread for a more in depth discussion on the topic. Feel free to discuss here, but I don't want to hijack his thread, which I sort of already did.