4 seems to be the best!

Yes, I loved the baby time, but the 2 & 3 time period not as much.  However having a 4 year old is great!  Having a potty trained child so we can so many things is great!  She's listening better, still strong willed, but I'm able to reason with her, and I'm learning how to deal with her (slow process).  Even considering a sibling.  If we can afford it.