First, with rates for AKL for a standard they can be as low as $119-$149 for Value....for Beach Club expect between $169-209 for good rates. Also keep in mind sometimes they offer specials that include park admission so it's hard to pin down the actual discount you're getting on the room...one year they did 7 nights for the price of 4.
Second, I have to say (having been there 3 times in 6 years while they were between the ages of infant and 8) that I would definitely consider a monorail resort if money were no object. We stayed at the AKL...just a hassle with the stroller on/off buses...the kids loved the resort but for mom/dad the frustration of getting to/from places was tiring when you're lugging the strollers and junk.
Now if you can afford monorail resorts...I think your kids would love the Polynesian...we got a rate of $194 a night a year and a half ago during the value season (September)...it's just so easy to hop on the monorail and go. I've never stayed at the Contemporary but if you elect there I would probably stay in the Tower v. Wing rooms. My kids just raved about the Polynesian but I would never pay more than $220 a night for it...I think it's worth it to pay about $60-70 extra a night for the monorail with little kids....now if they were teenagers I'd suggest BC/YC....and save the money.
Enjoy planning!!!
Tara