We have 3, a 3yo, a 2yo, and a 4 month old. I know that I'm not done, I've always wanted a bigger family, and I still do, but the size of our family is great now. I love the whole childbearing process, getting pregnant, pregnancy, giving birth, sweet new babies. I mean, I even still have froze sperm, can't let that go to waste.
I am ready for a break though. We'll think about #4 when these boys are well into elementary school. I may be a surrogate before then...we'll see.