Deluxes have some of the best dining in Disney. But lousy food courts.
The rooms at the "moderate" Deluxes are smaller than the other Deluxes.
We are now DVC members - after moving from Moderates to Deluxes. But even though I became a deluxe person - I think the moderates are a much better value for the dollar. It depends on what your dollar is worth to you. For us, it became worth extra $$$ per night to be close to the parks, the better theming (but the themeing is still excellent at the moderates), and bigger rooms, but we had the money to spend. The question is, what would you be spending the difference on?
questions to ask, how much time are you going to spend in the room, what parks are you visiting, what ages are your kids, and how dependant will you be on Disney transportation. You can't beat a monorail resort for traveling with more than one kid under four and spending lots of time in the MK. Disney transportation "tends" to be better from the Deluxes (which often have walk or dedicated (monorail/boat) access to at least one park). A family who spends time in their room can benefit from the extra space more than one traveling that will only use the room to sleep and shower. But a family traveling with pre-teens using the room to sleep and shower and driving or renting a car - why spend the money on a deluxe? Unless you've always wanted to stay at the Poly or don't have a budget.
(Gabrielle, some of the deluxes have excellent bike/walking paths as well, particularly around the Boardwalk and Wilderness Lodge).