Our family has different favorites, so I'll break it down by individual:
DH & DS (13):
Islands of Adventure
Universal Studios
Epcot
Me:
Epcot
IOA/ MK tie
Universal
IMHO, for a 1st time visit, MK is a must!!! I agree that SW is a very nice park, but living in Florida & having APs, we are bored with it. We have been to the WDW & UO parks too many times to count & still love the parks in our favorites lists.