I'm of the very small minority that considers Episode I the best of the prequels, so I have a soft spot for it.

Some of the designs are very nice and cool. Darth Maul's design was awesome, it's a shame he wasn't developed as a character, but he looks cool enough to have been the main villain in all three prequels. The Naboo starfighter is another design I really like even if it's impossible for R2 to fit in.

The Duel in Episode I is nicely choreographed, even if it's completely emotionless, it was with II and III that the lightsaber fights became too fast and non-sensical.

Williams's score for Episode I is terrific and the closest he got to the OT sound.

As for AOTC and ROTS, well, there's not a lot I can say that I like. Natalie Portman certainly is easy on the eyes.