What wieght oil do you use?

I have been a big fan of Mobil 1 the past 20 years (a number of 250,000+ mile engines including 4cyl turbos using mobil 1). The Barracuda still has the hot-rod slant 6 in it and it gets 15W-50 (the new 360 will likely run 10W-30), my Dakota gets 5w-30 in the winter and 10w-30 in the summer and the PT Cruiser gets 10W-30.