I have to admit, I've never really understood the Blackberry. Are there really emails that show up that absolutely cannot wait until you get to a computer? I assume any traveling businessman has a laptop, and lots of hotels these days have internet in the rooms (and if not, at least have a courtesy computer). I like my cell phone to be small and easy to pocket, the Blackberry has always seemed to be contrary to that.
Still, a very impressive piece of technology, and if it does the job for you, all the better!