We have three now, a 4yo boy, 2.75yo boy, and 6mo girl. We definitely want more. I actually began obsessing after DD was born about whether it would be one or two, and when that would be. I literally could not stop thinking about it for weeks until I had decided.
DH is in college now FT and working FT, so another would be hard right now. I finally decided on two more, in 3-5 years when DH is done with school. I'd like to have them close together like our first two since there will be such a big gap between DD and the next two (4-5 years or so.)