I like the idea behind a fold-away keyboard (droid 2). The always out design bugged me (droid pro), since you only need the keys accessible when actively typing something on the phone, which for me is only like 20% of my time using the phone. That means the other 80% when I'm browsing, playing, watching, talking, you have 30+ keys just taking up real estate making a big phone even bigger. This is why I personally never cared for Blackberrys.
Now, if you don't mind having a big phone, at least use all that real estate for a larger-than-life display (droid X). That's your prerogative. I personally like a decent sized screen, not too big, and the ability to slide out keys when I absolutely need them. My vote is therefore for Droid 2.