AAA identified 9 Five Diamond Hotels in Las Vegas for 2011: Aria Report & Casino, Bellagio, Encore Las Vegas, Four Seasons Hotel Las Vegas, Mandarin Oriental Las Vegas, Skylofts at the MGM Grand, The Palazzo Las Vegas, The Venetian Las Vegas, and Wynn Las Vegas. The Aria and Mandarin Oriental are new to the list.
I'm not that much of a gambler myself but one of the better externalises of gambling is that really great hotels in Las Vegas aren't reliant on room rates for profit. As such, if you are willing to brave the summer heat (weather.com says its 97 degrees there at the moment), 5 of the 9 hotels mentioned above are running nightly rates for under $200. There aren't many places where you can score Five Diamond luxury at those prices.
The Aria: Weekday, 2-night packages for $298
The Palazzo: $149 nightly rates with restaurant and spa coupons
The Venetian: $149 nightly rates with restaurant and spa coupons
Mandarin Oriental Las Vegas: $195 nightly rates
Four Seasons Las Vegas: $179 nightly rates
Of course if you ending up depositing vast sums in the casinos then you probably haven't come out on top, but if you are looking for luxury rooms in Vegas the season is looking decent so far.