If money is no object you only have 3 choices of places to stay:
Bellagio, Palazzo (Venetian) or Encore (Wynn). The choice will depend on what you value most, such as casino (Wynn and Venetian have fabulous casinos, whilst Bellagio mostly caters to higher-rollers). We have stayed many times at these 3 resorts and we love them all, for different reasons. The Palazzo o Venetian suites are fabulous; the Encore rooms are fresh and modern; Bellagio does not have equally huge rooms (but of course you can always opt for a suite) but the service here is second to none. Amazing spa, amazing gym: you are amongst the elite here.
If you are on a budget – you can safely choose from the still very good MGM, Mirage (we stay at these two resorts very often), Treasure Island (but the rooms are small at TI, so beware, though it’s a very nice little place in every aspect, though the pool area is a little too small for us) or, if you really need to save as much as possible, Montecarlo (the pool area here is not that great, though, just small and incredibly noisy: you can barely here each other scream). Below these you will seriously compromise on comfort, atmosphere, smells, noise, cigarette smoke everywhere or just an overall-run-down atmosphere you can only overlook if you are drunk all the time. A note on cigarette smoking: of the super cheap resorts, the Circus Circus is the only one which, in terms of rooms, have a real policy of smoking and non-smoking: if you are a smoker Circus Circus will treat you well and, if you are a non-smoker, you will be equally respected and they will assure you that you will not stay in a room where you breath other people’s smoke. Out of the low budget resorts, in our extensive experience, Circus Circus is the only one with excellent security and every customer is treated truly equally in this respect. Maybe because they cater for families too and not only to crazy-partiers, but if we are on a strict budget and want to breathe in our own room we always go here.