Starscream is definitely my favorite Decepticon (sorry, Megatron
). I'm quite impressed with how Tom Kenny's performance of him. This gentleman doesn't fail to deliver.
With the Autobots; it's a much more difficult choice for me. It's between Bumblebee and Ratchet, but I do like Prowl, too (didn't I say it was a tough one for me?). I also enjoy watching Sari in the series, definitely a great human character.
I don't have any of the toys (any idea when they come out?). Got any images of them Ditchy?