The Bellagio is trading on its name. The rooms are nothing special. Yes the furnishing are high quality, but without a lake view the room is fairly standard and not that big. The bathroom is very nice.
It is also 12 years old now and there are far better and newer hotels for similar money.
The Wynn was opened in 2005 and is very good, but I think the Encore is even better and it has only been open 18 months. The rooms are large with flat screen TV's in the lounge/bedroom and also in the bathroom. There is a separate lounge and bedroom area and the beds are extremely comfortable. Floor to ceiling windows with great views of the strip if you get a south facing room. It is at the north end of the main part of the strip so some might not like the location, but it is opposite the Fashion Show Mall where there are shops and restaurants.
You could also consider the Palazzo which is also quite new. We had a Fortuna suite there so I cannot comment on the standard rooms.
There is the new Aria and Vdara at City Center which only opened in December/January. We have stayed at the Aria and it was OK, but I won't be rushing back.
When are you going?
The Cosmopolitan opens in December and looks great. As far as I know all rooms have a balcony and kitchenette.
luci