Recommendations for a restaurant to celebrate a milestone birthday for a group of 9?

Celebrating a 70th birthday this month and looking for a special place to dine on a Saturday or Sunday night with six adults and three children under 10 years old. Trying to find somewhere nice and elegant (and welcoming of families with children) – possibly with a private room or table. Thanks in advance!

ETA – Anywhere in the loop or the suburbs is fine. Just want to make sure ambience, food and service are all excellent.