This is a very interesting topic

Me and DH always said we will plan one and then we will decide about the rest if and when we are emotionally and financially ready for more ( we did not want a set plan in stone ). But neither of us either thought more than two kids. I am now pregnant with for the first time with twins and we both know that we will probably not have more kids. But again we are not setting anything in stone. If in a few years we see that emotionally and financially we can handle another baby a we might consider it but I know the chances of this is rather slim.
I grew up in a big family as we where 4 kids. It defiantly has its benefits and down sides. As an adult I love having so many siblings a huge big family!!! It really is a blessing. As a child although I loved having siblings it was a constant battle for attention. With four kids parents attention is spread very thinly between all the kids and some time one or the other is left behind. Please do note that I am not saying this is the same in every case and please don't miss understand I grew up in an amazing, loving and caring home and I owe my parents every thing. All I am saying from my own experience I do not think it would be the right choice for me and my DH

I do think that big families awesome and I would not change mine for anything in the world