What would be true if creationism were true, but false if not? I don't mean "well, God would exist"; I mean what would we expect to happen differently?
Well, there's the whole "the universe is comprehensible" thing, which has been discussed in other places (and I do believe it's a great argument). But I just had an idea: the universe is huge. It has either been created by impersonal natural laws, or by God. In the second case, we expect it to have been created for our use, just like the Earth, and therefore at some point we will develop / discover a practical way of faster-than-light travel - just as we developed a way of crossing the oceans. Such an expectation is not warranted in the first case, since it's irrational to expect impersonal laws to care for our wishes.
So there. FTL technology. I can barely wait. grin