First let me say that I own a 2003 Rav4. I have a large 90 pound black lab. I'm already looking for something bigger because by the time we pack us, the dog, and all our stuff, the SUV is getting too small already. I can't imagine adding kids to that mix, and we're planning on having two kids in the future.
So definately, I think you'll find the Pruis and the CRV are going to be too small with multiple kids/dogs.
Personally, I've been looking at the 07 Rav4, which is bigger than mine and has 3 rows - which I figure, could be for my dog - and you could fit two dogs back there nicely, and then you could have up to three kids in the 2nd row.
I've always been looking at the Trailblazer - but the new ones don't have the 3rd row option. And I'm weary about the reliability of Chevys.
The toyota sienna is another good option if you don't mind minivans.
The toyota highlander is bigger than the rav4 - and it also comes in a Hybrid model, if you want to save on gas and help the environment.
Hope this helps!