I'm surprised Las Vegas doesn't have its own corner of Chowhound. anyway--here's my recent experience over New Years...
Kokomos at Mirage. Steaks looked good but were tasteless, fish was overcooked, dry and tough. Coffee was surprisingly good in the Euro style. Not a keeper.
Gallagher's steak house in New York New York. Steaks and prime rib were excellent. Stilton scalloped potatoes were a knock out. Don't order the coffee--haven't had coffee that bad since before United starting serving Starbucks.
Orchids Garden Dim Sum. Very good. We were surprised and pleased to find outselves almost the only occidentals in a large and very busy dim sum restaurant. We got there about 11am and the restaurant was half full. By 11:30 there was a waiting line. They serve in the "rolling carts" style which I like best.
Seafood Buffet at Rio. Still the best. Pigged out on about 4lbs of lobster. Rio is now giving you the option of taking a number and watching a board to tell you when to join the line. then the line lasts only about 20 minutes--much better crowd control model than the usual.
For seafood we did try Fremont Hotel but discovered the seafood buffet is served only on certain days--check with the hotel before going.