Def 7! There are 4 parks plus if you want to do Harry Potter there is Universal so 5 parks and you will want to do more than 1 day at Magic Kingdom and Epcot (at least we do 2 days of each of these when we go). Plus if you want to do any water park that is another day or a day. Seriously 7 is the absolute minimum we would go (but that is what we do every time). I am jealous!
Re: Would you do 6 or 7 days at Disney?