I have the same problem - for some reason, some keystroke combination on the fold-out keyboard of my droid triggers the 'send' command before I have finished typing it. So I get emails that just end before the thought is completed.
I've searched far and wide to find out if there is a 'send' keyboard shortcut, but I have not found it listed anywhere, but apparently there is one because I apparently type it in 1 out of 4 or so emails.
I'll try leaving out the email address, but you know, when you hit 'reply' that is not a very good option.
I try and type pretty fast on the fold out keyboard, but this problem is pretty serious and so it really slows me down.