Touch screens are not good for me because I like to type a lot. Also, the 8520 has such tiny buttons that my thumbs collide when trying to press them. Consequently, I'm currently using an 8800 as the keys are a decent size.
I'm still umming over upgrading my Indigo 8800 w/o camera to a Tour 9630 w/o camera. I can't take a camera-phone to work
The best Blackberry is the one that fits your needs the best.
With that said, the Blackberry 9850 would probably be the best for my needs. My business is expanding and having a smartphone with more power and a much larger screen are becoming critical assets for me.