No "Stayin' Alive" is not the new theme song of Burger King, which formally found itself in third place in the hamburger wars this week. It's the stick-in-your-head beat from the No. 2 bestselling soundtrack of all time, 1977's "Saturday Night Fever," and you can listen to a clip this morning at, of all places, the Wall Street Journal. Wendy's is the new No. 2 burger joint, but both chains are being whupped by McDonald's, which announced last night that CEO Jim Skinner is retiring and that president and COO Don Thompson will succeed him this summer.