While I think this is one of the most moronic questions in modern politics, I'll answer it, with my typical "in your face" style.
For purposes of this post, I'm going to change this question to "Which candidate would you most like to have a drink with?" as I'd like to work hard liquor into the equation.
I'd love to have a drink with both candidates.
My drink with John McCain: I'd challenge Johnny-boy to a shot-for-shot liquor consumption contest. Knowing my prowess with the drink, I'd be a shoe-in to win it. Additionally, knowing McCain's health problems, I think that he'd likely keel over dead halfway through the contest. That would solve the McCain problem. How beautiful it'd be... John McCain and I, trading friendly shots of Jameson (gotta drink real man shots with a Republican). Near the end of the first bottle, his heart gives out, and I'm still sober enough to attempt CPR. However, because of his age and medical conditions, he doesn't even make it to the hospital before he dies of "complications due to alcohol poisoning," even with the best attempts of the paramedics.
My drink with Barack Obama: Oh, that would be a hell of a night. We'd start off in one pub. He'd buy the first couple of rounds, and I'd buy the first round of shots. We'd be the life of the bar. We'd move on after a few rounds to another pub, one with a great band playing. We'd live it up over pint after pint. We'd talk about life, the music, everything except for politics because we'll never agree on them. We'd be almost as much fun as the band. It'd certainly be a night to remember. Even after such a great night, I wouldn't vote for him. I like Obama's charisma and personality. I just don't want him as a leader. Obama would be a friend, not a president to me.
Wait, I just killed one candidate, and refused to vote for another. Isn't the purpose of this exercise to show who I'd want as a president? Why yes it is. We haven't gotten to my choice for president yet. In the eyes of many Americans, there's more than two choices for president.
My third night out drinking with candidates, I'd like to go have a drink with Ron Paul.
My drink with Ron Paul: The evening would start off in a back corner of a local pub, likely with a great band playing. We would have chosen the back corner so we could still enjoy the music, but also be able to hear each other in conversation. I'd buy the first round - two perfect pints of Guinness. Ron and I would talk for hours on end about how to really fix this country. By the end of the evening, we would have solved the problems with the economy, oil prices, the war(s), education, and just about everything else - all with him never presenting a new idea. Ron Paul already has the solutions for this country. I'd just be a better man for having talked to him about them. Come November, I'd do just as I plan - write in a vote for Ron Paul. He is one man that is truly a leader.