I once had the displeasure of staying at the Imperial Palace with a good frient that was considered a high roller there. The only reason I agreed to stay there was that they were offering us (Really Him) free $1,000 tickets to the Tyson Holyfield fight (The Bite Fight). Even though meals were completly comped during the trip, the food was so bad we decided I would rather pay for food elsewhere.
My favorite Buffets in vegas are
1) Bellagio (just about any meal but dinner is the best) and its close to the Poker Room
2) Rio Seafood Buffet (Very reasonable for what you get)
3) My number one all time recommendation for the BEST BUFFET IN VEGAS.... The Sunday Stearling Brunch at Ballys. Lobster, Caviar, anything you desire and one of the nicest and most helpful waitstaffs around. The only drawback is the price which I believe is around $60 a head. Still in my opinion, well worth the trip.