I agree that kids DO like the PT more than OT. Working in a Toy Department for 5 years now, I've seen more than my share of kids and parents looking for or saking for particular characters.
I do get the occasional "Where's Luke?", but it's mostly asking for Clones, Mace or Yoda (w/ lightsaber)...
Hell, today I had a Mom ask why I didn't have any JAR JAR BINKS figures! I am NOT making that up to be a smartass either. She was a little pissed, and asked if those Collector guys bought them all up already this morning. I politely explained that he hasn't been out since ROTS 3 years ago, but she could probably get him cheap on eBay.
My own kids (14 & 12), prefer the PT even though they were born watching the OT, until they were 5 & 3. Once TPM came out, they were hooked, and think the OT is "boring" now....except for the saber duels that is.