I know you all will kill me for this, but...
You know what I think was the worst part of Episode I? Not Jar Jar; I liked Jar Jar. Some of him was stupid, but he wasn't that bad. Not Anakin; at first little Jake's acting seemed annoying and fake, but after watching a few tapes of myself at that age, I'd say he did pretty well. Some things were bad ("yipee") but overall, it was OK.
The worst thing about Episode I was...Natalie Portman. Her lines were delivered poorly, she seemed totally out of place all the time, and she was unconvincing overall. I don't even think it was a good casting decision. Carrie Fisher made a fabulous Princess Leia. She was tough, yet she could play the damsel in distress. She had the right look - not mind-numbingly beautiful, but pretty and regal. She had good chemistry with the other actors. Natalie Portman had none of these things in Episode I. She isn't even attractive in ANY way, much less the way that was important to the movie.
So, there's my opinion - flame away.