I love the Bellagio Fine Art Gallery!
Since this gallery changes the "theme" if you will bi-yearly, every time you come to Vegas there will likely be a different exhibit.
Also, this gallery is not an all-day, museum-like gallery. There will be around 20 paintings/sculptures, and that's that. Likely you will be able to experience the entire exhibit in an hour or less.
All of the exhibits are set to audio, and the audio is included in the ticket price. The tickets are $15 ($10 for students/residents/seniors) and worth every penny. Let's think about it....$15 can't even by you a margarita-by-the-yard. But it WILL by you an hour of art, culture, and history.