I would love to take my 6 yr old son on vacation and can't decide whether a trip to Disney World (he went to this location when he was 4) or San Diego. Or, if you have any other locations to recommend, I am all ears. Thanks everyone!

any rectory will do

Vivian, it would help to know where you live and what he enjoys doing. Is he more into outdoors stuff, museums, zoos/animals?

Check out Animal Kingdom Lodge in Walt Disney World. I am not into Disney World at all but saw this on "great hotels" on the travel channel. Wow, wild animals roam the grounds, too many other things that I have no time to tell you in post. Looks like great fun.
Hotel looks fantastick!

6 is perfect for Legoland, north of San Diego, and for Knotts Berry Farm which is about 75 minutes north. You can also hit the San Diego Wild Animal park in between, and Disneyland. Sea World in San Diego is also great. The ticket prices really add up, but for a 6 year old who's been to Disney World, I'd vote for Legoland, then Knotts...with the Wild Animal Park a close third.

san diego is a GREAT place. i'd skip knotsberry. there is plenty to do in and around san diego.