It's also worth noting, that quite a few people on the forums who've said they'd only consider a phone with a keyboard, have found the virtual keyboard on the Nexus One very good. There are some big improvements in Android 2.1 over previous versions, and also the bigger screen makes it much easier to hit the correct key.
There's also an keyboard coming out for Android soon called Swype which looks very promising. You just vaguely try and slide your finger over the virtual keyboard attempting to roughly hit the letter you want, and it figures out through a clever prediction system what you're trying to write, even if you completely miss the key you were aiming for. This makes it potentially much faster than a normal keyboard (no need to take your finger off the keyboard), and more accurate too... maybe...