I know the app is available for this phone. I know people happily (very happily, actually) using the app on Droid Xes.
I prefer the form factor of the Fascinate, the screen, the size. But before I decide between the Fascinate and the X, I'd like to hear from someone actually using the B&N NOOK App on this phone. I have no idea if the functionality would be different on 2.1 vs. 2.2... (It's supposed to run on anything higher than Android 1.6 so I assume it works on most any Android phone.)
I'm not interested in the Kindle app, as I don't deal with Amazon and I do own a NOOK. Hence I have a significant library of B&N books that I might want to read through the phone if/when I'm stuck without NOOK.
If NOOK doesn't work well, it's probably not a dealbreaker; I don't want to read on an LCD screen, but it would be handy to read a few pages when caught somewhere waiting that I didn't expect to have to wait. Now I people watch. 
Aside: Anybody know when the Bluefire Android app will appear? They casually throw that it while ready by spring in a paragraph about supported platforms on their site, but it says just "Spring."