You gotta try out Bacchanal if you are in Vegas, hands down the best buffet right now. It is quite pricey for a buffet ($30 for breakfast and $55 for dinner). If you want a good value and most bang for buck, I would come in near the end of the lunch hour (230ish) and they'll start dinner service at 3pm.
If you end up buying a BUFFET OF BUFFETS 24 Hour band...be aware that you pay a surcharge of $15-$25 PER visit. Still worth it though, the food is amazing.
There literally is EVERYTHING here and they use high quality ingredients (especially for a buffet!). I had dim sum, pho, eggs benedict, and the BEST bacon ever here for breakfast on one occasion. Can you say HANGOVER KILLER?!
Expect for 1+ hour waits if you go during peak times, so plan accordingly! :D