With March Madness under way, we're taking the opportunity to present out first burger tournament featuring 16 American burger chains. Get ready to take lots of polls—we're going to put up a different one every weekday for the next three weeks.

First up: McDonald's vs. Sonic. Poll closes tomorrow at 10 a.m. ET. Update (3/23/10): Sonic is the winner. Thanks for voting!

[For more burger bracket fun, check out San Antonio Burger Blog, Ulika Food Blog (Nashville), and Burger Business.]