Caesars Palace and the Four Seasons. (Courtesy Harrah's/Four Seasons Hotels & Resorts)

In Pictures: Best Hotels In Vegas Family-Friendly Luxury Hotels Billionaire-Owned Hotels The Gamblers And Money Behind Online Poker Europe's Most Luxurious Hotels

Wynn Las Vegas, which opened in 2005. It's a massive jade arc that contains a large waterfall in its nightclub, Tryst, not to mention a Ferrari/Maserati dealership.

Rather than rest on his laurels, Wynn decided to outdo himself by opening the $2.3 billion Encore casino right next door at the end of 2008. Sure, it was right in the middle of a recession, but Wynn didn't cut corners there, either: There are 5 restaurants and 11 high-end boutiques, and guests can even gamble by the pool.

In Pictures: Best Hotels In Vegas

The Vegas hotel industry is all about one-upping the neighbors--even if that neighbor is yourself. And it works: In 2009, even amidst an economic crisis, the city saw 36 million visitors drop more than $5 billion in casinos on the Strip (and more throughout the rest of the city). They stayed in the city's 150,000 hotel rooms at an occupancy rate over 80%--that rate hovered near 90% on weekends. Room rates in Las Vegas are still relatively low--around $90.

But when you're deciding on a hotel in Vegas, a decent room rate only answers one part of a larger question. Namely--what are you in the mood for?

We polled 10 luxury travel agents who live and breathe Vegas. They visit several times a year to keep their clients apprised of the latest developments, and they have strong opinions about what's worth a visit, and what's not.

"If a client comes to me with a hotel where they want to stay, I always ask, 'Why?' to try to find out how much they know about the property, and if they would really be happy there," says Monika Dystart, travel specialist at Sixth Star Travel in St. Louis.

Are you a high roller? Try Wynn Las Vegas, which features the only golf course on the Strip, or the Bellagio, where highly liquid visitors are given their own playing rooms. Partial to swimming pools? Check out the minor ocean at the Mandalay Bay, replete with waves lapping against a powdery sand beach. Is this a romantic trip? The Four Seasons takes serenity very seriously.

"Las Vegas is constantly evolving," says Anthony Adler, CEO of California-based Cruise and Resort, Inc. "New isn't good enough anymore. Each new property has to successfully raise the bar on luxury guest offerings. And the best part is, you can now find luxury options in Vegas without getting a penthouse suite."

In Pictures: Best Hotels In Vegas