I've always thought
Monica was a nice name and I actually have a friend with the name (17). I can see it making a comeback someday.
Monica and
Mona give me very different vibes as well, but I love
Mona! It's such a sweet name. I also like
Monique but I can't see myself ever actually considering it.
PNL:
http://www.behindthename.com/pnl/174843