When you think you have a good hand, sometimes the best strategy is to raise the bidding.

That's what Las Vegas is doing as high-end luxury suites are springing up along (and not far from) the city's four-mile Strip, including the Signature at MGM Grand and the Venetian's new Palazzo. Late next year, they'll be joined by two more - the Mandarin Oriental Las Vegas and the Harmon Hotel - at the $7.4 billion city-within-a-city MGM Mirage City Center. And that's just to name a few.

The idea is simple: Why be boxed into a room when, for a few dollars more (relatively speaking), you can have a suite ranging from 500 to 1,500 square feet filled with luxurious options?

As the differences in sizes would indicate, so do the amenities and the attitudes of the various luxury resorts.

At the Signature - which boasts three towers just minutes away from the green monster known as the MGM Grand - the goal is to give Vegas visitors a place "where they can get pampered during the day," said Signature vice president Frederic Luvisutto, who was closely involved in the design of the resort.

He continued: "More and more people want to go to Vegas to experience Vegas on their terms - go to the best restaurants, shows, concerts - but more and more people appreciate that during the day they can relax ... and not feel crowded," and yet be "literally two minutes away from the MGM Grand, where you can experience the action of the city."

To that end, the Signature boasts a non-smoking, non-casino environment. Inside the gated resort, every tower operates as a separate arrival experience, with its own intimate lobby and concierge desk. Luvisutto promises no lines.

The 550-square-foot junior suite includes a large bedroom with deluxe king bed, separate sitting area with entertainment center and kitchenette, while the bigger suites have fully equipped kitchens, parlors, more bathrooms and balconies. (Balconies are available in some of the junior suites.)

There is also 24-hour concierge service, valet parking, bell service and in-suite dining.

And while the Signature stresses the ability to get away from Vegas - a breather from the circus of the city - down the street at the Palazzo, the attitude is more about being on the Strip.

Ron Reese, vice president of communications for the Palazzo, recognizes a new phase in Las Vegas with the rise in "top-tier luxury offerings" at non-themed resorts.

He said the difference for the Palazzo is a convergence of overall luxury and amenities. Unlike the Signature, the Palazzo does have a casino, restaurants and shopping on site, including Las Vegas' first Barneys New York.

The suites themselves, which average around 700 square feet, sport sunken living rooms, marble baths, wireless Internet and other amenities you would expect to find in a luxury lodging establishment.

The Palazzo also includes the 134,000-square-foot Canyon Ranch SpaClub, while the dining includes restaurants by Mario Batali, Emeril Lagasse, Wolfgang Puck and Charlie Trotter. In April, "Jersey Boys," the 2006 Tony Award winner for best musical, will open at a new theater inside the resort. Plus, as Reese notes, the Palazzo is next to the Venetian, and near Fashion Show Mall, TI, the Mirage and the Wynn.

While the Signature and the Palazzo are on different high-end tracks, Anthony Curtis of the Las Vegas Advisor Web site (lasvegasadvisor.com) thinks there's plenty of room in Vegas for both - and a lot in between.

"The city was ripe for this type of influx," he said of the condos and hotels rising up around the city, a pattern reminiscent of Miami Beach.

Some of the brand names - the Palms (which is finishing up a luxury tower), the Venetian, the MGM Grand - will probably do just fine, Curtis maintains. But the glut of luxury condos could be problematic elsewhere in the market - notably at the smaller developments, some of which are miles from the Strip.

"Deals are different everywhere," he said. "Some are pure condo; people are living in them, reselling them. Others are cooperatives with the casinos for resale to their guests. It gets complicated."

Curtis, in fact, looked into buying a luxury condo as an investment but decided against it.

For travelers to Vegas - and there were more than 39 million visitors to Sin City last year - a luxury suite may be what they're looking for.

"The appeal is the cachet. The Strip is the hottest four-mile piece of land in the world," Curtis said. "It's just a powerful brand."

And having a luxury suite on that piece of real estate gives the owner a feeling of being a cut above.

"It depends what people want. It depends on their utility," Curtis said. "If they think it's cool to say, `I'm part of this big tower and I've got this room that is not a hotel room,' then there is value in that. ...

"There is a lot of posing in Vegas, so people come here and do things they wouldn't normally do. So, well, hell - in for a penny, in for a pound."

The price, however, might not be that steep. The low end of these suites in late February went for around $199 a night, which is comparable to some hotel rooms on the Strip.

Still, Curtis said, if you're looking to do Vegas as a bargain, why spend another $60 or even $160 per night?

That isn't the way Sin City is going, though, at least building-wise. Next year, two luxury complexes, the Mandarin Oriental and the Harmon Hotel & Residences, will open as part of City Center, which Curtis marvels at as he watches it go up ("one of the great construction projects of all time"). It's part of what he calls the "extended fourth wave of building in Vegas."

Eventually, that may mean a chance for bargains.

"I'm not saying Vegas is overbuilt, but there will be target opportunities for high-end bargain-seekers to get deals," he said.

The Palazzo's Reese cautions that you can never tell when bargains will be available, though, because of the number of convention bookings. So don't expect that a Tuesday in August will be inexpensive; the plumbers' union may be in town.

But, he said, if you compare the Palazzo suite at $300-plus a night to the same thing in New York, London or Paris, "That room's going to stand up as a good value."

As for the luxury-suite boom going bust, Reese doesn't think so. "We show people a cover of a Life magazine from 1955 that has a couple of can-can girls on the cover, and it says, `Las Vegas, is the boom overextended?' At the time there were between 2,000 and 3,000 hotel rooms. Now we're approaching 140,000."

WANT TO GO?

SIGNATURE AT MGM GRAND: 145 E. Harmon Ave., Las Vegas. www.signaturemgmgrand.com (877) 612-2121.

PALAZZO: 3325 Las Vegas Blvd. S. www.palazzolasvegas.com

(866) 263-3001.