We just got a 2008 Toyota Sienna and it rocks. We test drove all of it's competitors and it was the best (in our opinion) by far! It has the most head/leg room, best gas mileage, more power, comfier seats. We got the 8-passenger LE version and the 8th seat is a normal-sized seat. (It's in the middle of the middle row.) That's where we put my son's car seat so he can see out the front windshield on trips! I babysit so I have another car seat next to my son's and the other day I had to put yet another one on the other side. It was a bulky one, too, and it fit fine. (Plus I had three kids in the back. They have an older version and they were even saying how much roomier it was back there.)
The back seats fold down into the floor and the middle seats fold up and can be taken out if needed. If the seats are all up, the storage in the back is awesome - very deep and wide. (My son's jogger will fit in it, and it's rather wide.) If they are all out, you could honestly haul drywall if you had to!