I think alot of us have a preferred program, but keep a second-tier program for small and medium towns with limited choices. No Starwood in Spokane. No more Marriott in Coeur d' Alene. Hilton in Missoula is booked from here to 2012 etc., etc.
Then when you go to choose a second-tier program based on wide coverage, you quickly find out two things about CP: Minimal promos and Points expire.
From that angle, IHG and even BW trump CP.
Points expiring sucks.
(says the guy who lost a bunch of LaQuinta points last month)