Grab a comprehensive guide book - the parks are SO much different now. (Before our trip in Apr '09, my last trip was '99 - I had to relearn the place!)
You've already got a base knowledge of the parks, but since the kids are older now, your touring plans (and expectations) are completely different.
Get a folder and keep print outs of things you've learned or consider doing on your trip. I kept all of my tips in a single word file, printed it out, and kept it in my Passporter for our trip. Next fall, the stakes are bigger as I'm meeting up with a friend PLUS my family will be going, we're doing the dining plan, coordinating flights, different hotels, etc... so my lone page is turning into a volume of information that I've collected from here and other places online.
I'm not a stringent planner, like I don't map out every minute of my day, BUT I do like to know as much as I can about wherever we are going in case I need a backup plan OR a change of pace.
I've asked for the Unofficial Guide for Christmas to accompany my Passporter.
Lurking around here is an extremely valuable resource as well. Trip reports and other people's questions/answers has been so informative.
HTH!