I've watched the old episodes too (like 'omg killer inflatable chair' old) and I still think Donna was my favorite companion. x3 For one, there was no crazy love thing going on between her and the Doctor; they were like brother and sister. They were just awesome together.
Though the big ending of season four was a little too...insane. I was super depressed that Donna had to forget all about the Doctor...I hope one day she makes a comeback. Maybe even as DoctorDonna. >D
I liked the platonicness, I don't mind the companions having a crush on the doctor, but she was a nice breather after the uber-romance of rose and the depressing and somewhat tedious unrequited angst of martha. Her and the Doctor we an amazing duo. I agree about the finale too, I think they tried to do too much all at once and it was crazy, then capped it off with the Donna tradgedy. D,:
Donna quickly grew to be my favorite too, I'd say. She was just so much more entertaining as a character than Martha or Rose! They were a little bland but Donna had a little more kick to her. Heh.
Just post some - I find when I can't quite draw something there's usually a point where I go "screw it!" and complete one version even if it's not quite right, just to get something done. It helps me not get constantly stuck in the sketch stage.