The far corner is your best bet, but it doesn't mean it's a good bet. Them's the breaks, and when it comes to NYC taxis, those are the only brakes you're going to get.
If you've got the manpower, the wisest move is to occupy every part of your intersection as if it were a game of Risk. Send scouts upriver like you're Ulysses S. Grant. And, despite having what amounts to be four-hundred dollar walkie-talkies in your pockets, be sure to yell and scream at each other from across the street when you finally find a car. That way, by the time you get your friends' attention, some savvier hailer has stolen your cab from right under your nose. And with your companions jaywalking their way towards you, you've now lost your other corners as well, just like you lost Ukraine. You suck at Risk, don't you?
The moral of the story? Be the savvy guy who stole the cab.