For 5, I would MAYBE choose an SUV. We own a 07 Hyundai Santa Fe and love it. It has perfect leg room in the 2nd row seat, and you can even get a 3rd row seat if you really want it, but its extremely cramped and I don't even know how someone would attempt to get back there.
For both 5 or 6, I would choose a Minivan. Here are good choices:
1. Honda Oddessy
2. Dodge Grand Caravan/Chrysler Town and Country (Same Thing)
3. Toyota Sienna
4. Kia Seddona/Hyundai Entorage (Same Thing)
If you see anything about a Chevrolet Uplander, STAY AWAY! My extended family, 2 different families, bought this problem prone vehicle, and they both are night meres. The power sliding doors are a mess- unsafe, and nearly shut on one of my young nephews. We had to pull him out of there, and tried putting force on the door but it kept closing.
Also, moldings have fallen off, and just bad quality. (This is the only GM vehicle that I do not stand by).
You cannot go wrong with the Honda Oddessy, and the Toyota Sienna is good too. Both extremley Reliable. The Grand Caravan/Town and Country are good cars, and are from the company who started the minivan. They have neat features, and are pretty good. Not as reliable though.
Last, but not least, is the Hyundai Entourage/Kia Sedonna. They are newer minivans, that have great safety, like all the others on the list, and have a great warranty (they Hyundai/Kia 5 yr/100,000 mile warranty).
So any on that list are good choices or the SUV mentioned at the top.
(the 08 GMC Envoy is also a good SUV choice)
Source: My own experiences, www.edmunds.com