Gonna go against the grain and say I'm really not a newborn fan. Maybe my shocking PND didn't leave a good taste the first time, but no scrap that, I really didn't enjoy my time as a NICU nurse and that was pre kids and i could give them back....

2-3 is my favourite in terms of discovering personality and independence. They aren't a 'baby' anymore and can do a bit for themselves, but they are still very much all about you.
But saying that, while 4-5 has been a challenge, my 4-5yo has been through a pretty challenging year, and now as I watch her turn into an older child I am amazed by her. By her creativeness, her affinity with knowledge, her relationship with her brother. How she's SO independent, yet still so totally reliant as Nate is.