Originally Posted by SSGN_Doc
I don't currently have a center fire revolver.
Doc, I found your problem.
My vote would be for the .357 over the other choices you're pondering. The GP100 is a heck of a wheel gun and I'm quite confident you will be happy with it.
But if you really are leaning towards .40 S&W because of the price of ammo and availability of it, the obvious answer is "go with what fits your hand the best."
Another to consider of course is the M&P line. That's my personal preference for polymer guns. You can get a 40/357 and get barrels/mags for 40/357/9mm. Three guns in one.