Neither of my girls have gone to daycare, and while they do come into contact with other kids at the park, their cousins etc their whole "socialisation" is dealing with each other on a daily basis. DD1 started kindy this year and from all reports is a very social little kid with her classmates with no problems arising from not having had the daycare experience.

I think daycare is a really personal decision, and it also depends on the individual child. I have no doubt DD1 would have enjoyed daycare. I'm not sure DD2 would.