Obviously, a lot of them have impressed me... Ware, Pettiti, Canty, Thompson... all have been great.
Who impresses me with his athleticism though, has been Burnett. I know he isn't playing a whole lot, but then a lot of very good rookies don't crack the lineup until somewhere in the middle of their first year, so he still may get a lot of playing time.
But where Burnett really impresses me is just watching his athleticism. When he goes after the QB like he did in the preseason, he looks like he's shot out of a cannon. And when he moves out on the field, he just looks like the best athlete out there, which he may be. IMO he moves like a CB but he has LB size. What's keeping him off the field is between his ears and that is going to improve with each game.
You watch; once that guy starts playing a lot he's going to be noticed on every play, and he'll make some big plays.
So impressed as far as production would be Ware, Pettiti, Canty and Thompson. Impressed as far as what I see when he plays would be Burnett.