good news: No one on this site is wrong--all of the deluxes are great.
Bad News: Tough choice! but if that's your biggest problem, you are very lucky indeed!
Here's my two cents:
Poly: FABULOUS theming, great eating, big rooms, nice views, on the monorail, and tiki torches lighting the trails!! cool stuff
Contemp: IF you are in the tower, its super cool to be there, all views are fabulous, closest to MK, GREAT place for recreation--that's where you rent boats, ski-doo's, para sail, etc.-- on the monorail, lots of amenities, and very newly remodeled rooms.
If you get stuck at the end of the garden wing, though, you are FAR from the everything, and the views can be so so. There is also a lot of remodeling going on in the common areas too.
Wilderness: FABULOUS theming, great pool, smaller rooms, seems very "tucked away"--even if you don't stay there, I would recommend a visit for dinner or just to walk around. Its appeal is also its downfall: because it's tucked away, there is no monorail, and there is not much within easy reach beyond its walls. (a nice little hike to fort wilderness is fun, though)
YaBC/Boardwalk: LOCATION LOCATION LOCATION--because these large resorts are so close and/or connected, you are really staying at all of them when you choose one. LOTS of eating, recreation, and pool choices. Close to Epcot and MGM (you can walk). bus and boat to theme parks, and even a small nightlife independent of the parks. Rooms are nice, but not as big as poly or contemp. Views are hit or miss too.
AKLodge: What can you say? for theming, its OUTSTANDING. How can you compete with giraffes and wildebeests (or whatever they are)? This one is also a destination all its own even if you don't stay there. Go for a meal at BOMA. (Jiko too). Really, its only downfall is that it is FAR from everything except Animal Kingdom. This may, however, be a plus for you. The bus system is good, but, like all mass transit, it's not flawless.
Grand FL: monorail, lots of amenities, great rooms, stylish, and even though I can say nothing wrong about it, I would not stay again. I just like some of the others so much better.
That's my two cents
You can't go wrong, really.
One thing that might seal the deal for you--do some research into the programs and offerings for the kids your age in terms of special activities and recreation offered AT THE RESORT ITSELF. At Boardwalk, for instance, they have surry bikes that you can rent and drive around. At some resorts, they have "storytime" readings in the lobby. At the Grand FL, they have a high tea, and a Mary Poppins character meal. At YaBC, they have kid's guided fishing excursions.
If it all sounds good, it may make your decision more complicated, but usually that can help you choose what's best for your family.