D.P.
I also suggest renting out a hall (firehouse, VFW, etc) or even sometimes Restaurants have private rooms you can use too. I would suggest however some kind of entertainment for the children invited (clown, magician, face painting, balloons, etc). Kids get bored easily. Another suggestion would be to make sure you set up a special table for kids to do activities (cheap crafts, coloring, word seach books). I've done this in the past and both the kids and their parents have a good time since the kids are keeping busy. I'm sure any theme you go with is going to be great. Enjoy every minute.