With my first I had to go back to work after only 6 weeks. I spent every waking minute with her when I wasn't working, and she is one of the most well mannered kids I know, very sweet. Family helped a lot which I am sure had some affect on her behavior. My youngest I stayed home with. She is slightly more hyper, but still, sweet kid. I think it just all depends on how you interact with them when they are with you. (speaking generally). If Bacon and I have a kid, I will keep the child home with me and try to work as much as I can around their sleep/feeding/wake schedule, and I am sure once they start to crawl around I will have to put them in daycare.
I prefer daycares that are more like pre-preschools as opposed to a place that just watches them play.