We also have 3 kids, and we have a 3rd row SUV and a truck. 3rd row SUV is solid for trips, carpool, and other things.
Truck is great for days like today where we had a canopy, large cooler, 4 folding chairs, life jackets, and other lake stuff. We could have likely crammed it all into the SUV, but I like the peace of mind and versatility that comes with the space the truck offers is nice.