I rarely see people mention it but the Four Seasons is far and away my favorite place to stay in Vegas. It is comprised of the top 4 floors of Mandalay Bay but has a completely separate entrance and set of elevators. To me it has all of the benefits of a top level hotel with none of the drawbacks that come from staying in a casino. However, with it being located on top of Mandalay Bay you have great casino access. You also have access to the Four Seasons pool which is the best in Vegas if you are looking for a place to actually relax along with access to the Mandalay Bay pool if you want the typical Vegas pool experience. It might not be the place I would stay if I were going with a group of guys but if I am taking the wife that is the only place we will stay.
Breakfast - second Mona Mi Gabi in Paris, sit on the patio even if you have to wait
Sunday Brunch - Border Grille in Mandalay Bay, they have unlimited Memosas and Bloody Marys along with an unlimited tapas style brunch, really good
Other favorites - Lotus of Siam, Tacos El Gordo, Hash House a Go Go, Peppermill
Personally I am not a fan of the high end steak houses. I can get equal food and service at the Ranchers Club for 1/3 of the price. It's just not worth it to me but your mileage may vary.