Best business smartphone

I'm in the market for a new phone. I presently have a Vario 3 on
T-Mobile with Web'n'Walk. It's bulk and battery life get me down. I
never use the separate keyboard. I do surf, use wifi and send and
receive emails from my Virgin Mobile account. and sync my contacts and
calendar with my laptop Outlook.

What should I choose? A Blackberry? Is the 8820 due out on T-Mobile?
Samsung? Nokia N95.

I'm not too bothered about a camera or music.

Thanks