OP, Both are great handguns. If you're going to end up with both of them sooner or later, then it guess it really doesn't matter which you buy first. And by the way, I'd take a CZ 75 over a P226. My 2 cents worth.
Also, just a heads up on your desire to own a CZ 75BD Stainless: Maybe I'm not as up to date on CZ's as I should be, but as far as I know, the CZ 75 stainless does not come with a "BD" designation. The CZ 75 BD is a de-cocker model with no safety. I think the only version of the stainless CZ 75 is the "B" model, which does not have a de-cocker, but does have a safety.
Personally I prefer CZ's de-cocker guns (SP-01 Tactical, P-01, P-06, PCR, 75BD, ect), but if I wanted a CZ in stainless, I wouldn't let the fact that it does not have de-cocker stop me from buying it.