blackberry! i've had the pearl and the curve and i just currently got the storm (verizon)
the pearl is a good choice if you like smaller phones, has the same or close to the same capabilities as the curve just not the full qwerty keyboard. the texting you get used to after a while.. the pearl auto-text bothered me a lot though lol. the qwerty keyboard on the curve is easier to text with but i always had to text with both hands. if i had at&t i'd get the
blackberry bold! its 3g & has wifi as does the iphone. the camera on the bold is pretty sweet as well. the bold is pretty pricey though if youre upgrading & i think at&t has a sale going on with curves right now anyway.
another qwerty phone you could look at is the samsung blackjack II.