Blackberry is fairly pointless unless your company / whatever runs a Blackberry email server. Treos, on the other hand, are perfectly capable of coping with normal email standards that have been around for donkey's years - I run an IMAP mailserver on my desktop PC and the Chatteremail mail client on my Treo, does everything the whole proprietary, monthly-charge Blackberry system does for no money besides the cost of registering Chatteremail.
OTOH, I keep finding that I don't _use_ it that much - my email can really wait till I get home. Unless you're 100% sure you really NEED a smartphone, you may find yourself in my position a year down the line - looking at a nice, small featurephone with a great camera, like the K750 / W800i, and wondering why you didn't get one of those in the first place.