I just went through the same decision myself recently. I was set on the X at first, just because of the huge screen and hdmi out which is pretty cool. However, my previous phone was the Droid Eris (aka HTC Hero on other networks), and the all touchscreen interface really bugged me after a while -- I think having a physical keyboard is a lot more convenient sometimes, even with Swype or SwiftKey. I ended up getting the Pro, and I'm quite happy with it, I really like the keyboard. However there are times I wish I went with Droid 2 Global instead -- bigger screen/keyboard, and faster processor. Still a tough call though because I really like having a portrait keyboard, I think I can type faster on it.
If you send more than the occasional email or long text, I would recommend getting one with a keyboard. Obviously the Droid X is the best multimedia experience, but ask yourself if you're really going to be watching many (any) movies on it. As far as game play goes, my Pro has the smallest screen of the 3 and Angry Birds looks and plays great on it, but that extra half inch always helps.