Hi K.,
You have a lot of good suggestions here already. I've been lucky to be in two book clubs in two cities and they have both been wonderful, bringing new friends and much fun. What I found when my son was younger was that I needed some mental stimulation that didn't involve kiddos!
Based on experience, I think it's good to have some structure for the group and to bring that forward early. It's good if one or two people take the lead to keep everyone informed and reminded. I think it works best to keep the group size around 6 - 8 so everyone gets a chance to talk. There IS definitely a thing as too many people in a book club! Plus you want to have space in your home to seat everyone comfortably.
We've found it worked best for us (in both groups) to let the hostess choose the book for her turn but it helps to discuss possible books each time we meet to get a feel for the response. That way, if someone has an objection they can plan ahead to bow out or another book can be chosen. (I like the idea of a vote but if you have young children you may not have the time to manage that--let alone get the book read!)
It depends on the hostess and doesn't always work, but we've enjoyed foods that fit the theme of the book...but honestly, we are all usually so happy just to get out that anything works! In one group, some months we'd each just bring an appetizer, salad, dessert, bottle of wine, whatever. In another group we take turns and the hostess handles everything. Both ways work well.
Three times we have invited local authors to visit our book clubs and that's been fun. We also just heard that some authors will chat via Skype or on a conference call during your discussion; we may try that.
One last suggestion is about your first book. "Angry Housewives Eating Bon-Bons: A Novel" by Lorna Landvik inspired me to start my first book club. It's about a group of neighbors with various personalities and lives who start a book club and share the times of their lives. The title is misleading but I think you'd really enjoy reading it before you start or as your selection early into your new club.
Good luck and have fun! In my current neighborhood we often say that Book Club Day is our favorite day of the month!
p.s. Once you put the word out that you are in a book club you'll get all kinds of suggestions for books from everyone and everywhere--you could even post a request here on Mamapedia. In addition to the Bon-Bon book I mentioned above, a recent book my group read and loved was "Hotel on the Corner of Bitter and Sweet" by Jamie Ford. I've noticed that Books-A-Million has a book club section as well as smaller local book stores--lots of ideas for both fiction and non-fiction there.