You need to sit down with your family and make a plan:
I. What needs to be saved from the house?
II. How is it going to be saved?
a. is going to evacuate with you?
1. who is going to move it to the evacuation vehicle?
b. is it going to be sealed up and left behind?
1. who is it going to be sealed up?
2. who is responsible for sealing it up?
III. When do you set the plan into motion?
IV. In what order will things be evacuated/sealed?

Houston floods every few years and we learned that without a plan it's very difficult to do anything effectively when you're in a panic because the water creeping closer and closer to your door. Arguing about what needs to be saved at the moment when saving is required is NOT a good use of time.

You already have your Emergency Binder ready to go, right?

Also note, the plan will take a lot longer to do in real life than you think it will take.
-Blast, speaking from experience (google tropical storm Allison, Houston, TX)