I was born the same year Episode IV came out (1977), and I remember when I went to see Episode VI when I was six and fell in love with Star Wars. I had like 75 of the original 1980's Star Wars figures plus the Vader figure carrying case. So imagine my response when Episode I came out, just were worthy of the original trilogy. Like this rapper the Ambassador once said after Episode I came out, "...not the same like Star Wars before Luke's born..." that's exactly how I felt.
For me, it's only certain aspects of Episode I-III that are worthy of remembering. Biggest one would definitely have to the first time I saw Yoda pull out his saber and going to work. That one scene managed to salvage the rest of Episode II for me.
Next would be Samuel Jackson as Mace Windu, the only dude in the galaxy to lay Palpatine/Darth Sidious flat on his back in a fight(not even Yoda could say that), and the one who created a 7th lightsaber fighting style. There were only 6 before that, check this interesting link on lightsaber combat http://en.wikipedia.org/wiki/Lightsaber_combat
. And of course, Ray Park as Darth Maul was memorable.
If anything Episode III was worth seeing simply because you didn't need to see Episode I or II to understand the story, Episode pretty much explained the preceding story points okay. That and seeing Obi-wan teach Anakin some manners.