I maybe in minority, but I chose the X precisely because it's already been out for a bit. To me a phone is not just a processor or a screen. It's a combination of a form factor, signal strength, sound, features, bugs, and update pathway. Even with the OG Droid I waited until the reviews were in and the bugs were known. I bought my X on Nov 11, so I'm still within the returnable window, but after running Rubix 1.9.0 on it and realizing that it has the combination of all factors I need, I intend to keep it. Yes, other phones are coming up, but to me a KNOWN stellar battery life, very large development community, great screen, diversity antennas, etc. is exactly why I'll stick with the X. Also, as more and more phones are released, I expect the development community to become more diluted, as there will be more phones that developers can choose to work on. Also, as we saw with the X and Incredible, if you wait past the first day or two (until the user reviews are in), there may be no stock available and then you're screwed for a few months.
I think the question is does X fit what you need or not. There will always be a (perfect and magical) unknown around the corner. To me, after spending close to a month with X, the answer was a yes.
Just my two cents.