I think it's really sweet how much thought you guys all seem to be putting into such special occasions! All of your ideas sound great. If you decide to go to one of the better hotels, flowers and champagne in the room are a good idea. But if the hotel has a spa or salon, consider getting her something nice like a manicure and pedicure or perhaps having the both of you get massages either before dinner or the next morning. You'll gain some serious brownie points for something like that!
I'm very impressed with all of your thoughtfulness!!