We booked six nights at Bellagio two weeks before Christmas. This is lower price time period so we got a very good room rate and airfare package.

I had seen Bellagio on a previous trip to The Venetian in May and thought the lobby and conservatory were wonderful, an understatement.
My husband upgraded our room at check-in to a lake view and this is worth the $40 a day cost - it was like having continuous entertainment from the water show every afternoon and evening - its especially spectacular at night. You can get the sound via the room's cable TV set and the muscial choices are terrific from pop, to classics. A really great idea, all round, by the creators of this incredible pleasure palace.
The buffet was excellent - we had breakfast almost every morning there and sometimes lunch.
On the restaurants at Bellagio - many have just two seatings- 6:30 and 8:30 p.m. I didn't find this very convenient so we missed Prime. I also would like to try Aqua. We did go to Picasso, to see the paintings. The food was excellent as was the service. Pricey, though.
The art gallery was wonderful, with a new collection we had not seen in May.
Pool area had some areas closed but the spa was fine.
The glorious Conservatory was dressed for Chirstmas and it was a great treat.
I did some shopping - their signature tops and shirts are really nice. I was, for the first time in Las Vegas, not lucky in the casino, but it is a beautiful casino - quiet and very elegant.
There is a piano bar that serves afternoon tea - another wonderful treat and plenty of people passing by,
I shopped on the last day over at Paris for great bread, sauces and pate to take home. We discovered their buffet and it is the best buffet I've ever had with a great choice of regional French dishes and really tremendous breads, cheese, fruit and desserts. We only waited a few minutes to get in - possibly because I asked for a smoking area - that's always faster. We were led to a charming room which was quiet and pleasant. Wine by the glass was a good buy. I recommend this for lunch. Have not tried breakfast or dinner there.
Bellagio room and staff were top notch - a perfect place to stay.