From Amy Thomas, author of Paris, My Sweet, a love affair with Paris, New York, sweets and travel.
Very tough one. But since it's good people-watching season, I'm going to go with dinner reservations. La Mom An American Mom in Paris
Reservations - I like that there is a natural end point. At someone's home, you can feel obligated to stay til late. If you are the hostess, sometimes you can't get them to leave!
I'll be the first to vote for dinner party. Depends on who's hosting, though. (As long as it's not me :)
Reservations, by all means. Let other peoople do the cooking and cleaning up!
Moi, I'll take reservations 8 nights a month, and 2 dinner parties. Not that I'm an anal planner or anything...