Mitchell Feigenbaum has, for the last ~17 years, been my vote for the next Nobel Laureate in Physics. It is a rare thing to derive an irrational fundamental mathematical constant that appears in nature. The Feigenbaum constants are as fundamental as e and \pi, and they are readily observed experimentally (though, necessarily, not to full precision :) ).
Godspeed, Dr. Feigenbaum. Thank you.