I was reading an interview with John Jorgenson and he said he has alternates between 2 picks. One is a 5mm Wegen Fatone and the other is a tortoiseshell pick that is modeled on the Wegen but with less of a point and a warmer sound.
He has two of the tortoiseshell picks that he bought for $100 each. They are the picks he uses 90% of the time, unless he wants more articulation or a brighter sound.
I read this in the July 2010 Guitar Player magazine.