L.
I have a nanny for my two kids, 2 and 5 months and wouldn't have it any other way. I feel that we are a team and I still get to make the decisions on my kids napping, food, etc.
For socialization I have the nanny
take my son to classes where the baby can tag along and he gets his socialization that way. Also, they go to the Park and my nanny has made friends and they are making play dates for further socialization. I let her know that she could have a friend with her charge over.
I work from home on fridays and have a playgroup on that day. Also, you can take your 1 year old to classes on Sat.
All classes don't have to cost a lot either, we use the Park district and their classes are only $30 for 10 weeks.
Ultimately, you have to do what you feel most comfortable with. Daycare or in home car is good, it's just what works best for your family.