That would be a great trip for your family.  I would recommend Marriott's Aruba Surf Club with kids of that age as they would love the lazy river at the resort.  There is plenty to do at the resort (pool, ocean, activities, etc.) but also some fun things to do if you want to venture off the resort.  If you rent a car, there are other beaches on the island you can explore like Baby Beach.  We also enjoyed a safari tour with ABC Tours (http://abc-aruba.com/)… your kids would really enjoy that.  If your kids like animals, there is Philips Animal Garden (http://www.philipsanimalgarden.com/).  They would likely have fun on DePalm Island for a day (http://www.depalmtours.com/de-palm-island).  I think you would find plenty to do to fill your time there. 

My children are a little older but love it.  Definitely do Surf Club instead of Ocean Club with kids.  The slides and lazy river will be a hit.  Ocean Club is nice, but seems much more adult oriented (i.e. quieter).If you don't mind a ride, that Flying Fishbone rocks for dinner where you have dinner on the sand (or even in the water)

You will love the Surf a Club.  There is so much for your kids to do.  We go over year in February when my son is off from school.  November is the rainiest month in Aruba BUT they only get about 20 inches of rain in an entire year.  Rain in Aruba is often a ten minute shower.  We usually hide out under our palapa or umbrella and wait it out.  There is a bowling alley close by for night time activities, Bushiri Go karting, a movie theatre and the a surf club has a great game room.  Feel free to PM me any questions.