Las Vegas, city of sin. But it's also a city of numbers.

Each year, more than 40 million people visit, bringing with them $50 billion to spend at casinos, clubs and strip joints. In recent years, an increasing portion of that pot is going toward Las Vegas' world-class restaurant scene.

There's a good news/bad news scenario. Bad news first: It's undeniably hard to get seats at the most popular places, especially during prime convention time. The good news: Every year, more exciting restaurants expand beyond the Strip, thanks in part to locally based businesses like Zappos that have re-energized different areas around the city.

Here are five restaurants worth booking ahead, plus a few spots off the Strip that make for an excellent Plan B.

Top tables on the Strip

Carbone: If there's a place outside Manhattan that can evoke the glory days of Italian American dining, where tuxedoed waiters tell bad jokes as they toss your Caesar salad tableside, it's Vegas. The second outpost of the cult restaurant from Mario Carbone and Rich Torrisi channels the New York original, with a red neon sign in the Aria casino hallway. There are the signature favorites, like spicy rigatoni vodka and veal parmesan. But here, you also find deep banquettes, private dining and a larger menu, including dishes like bone-in New York strip and a melt-in-your-mouth lasagna layered with delicate egg crêpes and black truffles.

Carnevino: Meat-loving Vegas has more steakhouses than just about any other place on Earth. One of the best is Carnevino, from Mario Batali, who opened it in the Palazzo at the Venetian in 2008. Then, he could have simply rolled out an outpost of his renowned restaurant Babbo, but instead dreamed up this gem, where you can eat both specially dry-aged, well-marbled steaks and amazing, gut-busting pastas. Not every notable Vegas restaurant is open for lunch, but Carnevino is; it serves a $65 martini lunch ($50 if you forgo the cocktail, but why?) with the choice of tagliatelle Bolognese or filet mignon.

Libertine Social: When he opened his first Vegas restaurant, the excellent Sage at Aria, Shawn McClain relocated to Nevada. This marked a big change from the drive-by habits of other chefs. Maybe because the city is his home, McClain is treating his third restaurant, Libertine Social at Mandalay Bay, like a house party, with a vast range of snacks and spreads, from warm Dungeness crab dip to shaved country ham. The bar scene is great, too.

Morimoto Las Vegas: In October, Iron Chef Masaharu Morimoto opened his first restaurant in Vegas, at the MGM Grand (he has almost a dozen locations worldwide, from New Delhi to Mexico City). In Vegas, the Nobu alum highlights his hybrid Japanese cooking like tuna pizza with anchovy aioli, and yellowtail pastrami, as well as a sushi selection that includes the intricate, oft-Instagrammed Morimoto stained glass rolls.

Joël Robuchon: On the list of the world's top chef outposts in Vegas are Guy Savoy at Caesars Palace, Pierre Gagnaire at the Mandarin Oriental and Joël Robuchon in the Mansion at the MGM Grand. In a marble-floored townhouse, Robuchon offers an over-the-top 16-course prix fixe menu that begins with Osetra caviar and moves on to choices like foie gras and potato carpaccio with black truffles. All this comes at a cost: $425, not including tax and tip. The less expensive option is L'Atelier de Joël Robuchon, which features counter seating and steak tartare with fries.

The best of the rest

Here are five places worth a trip off the Strip.

Abriya Raku: Like many chefs in Vegas, Batali is a fan of this Japanese grill. "I LOVE Raku on Spring Mountain Road," he said via e-mail. "It's one of my top five restaurants in the entire U.S. You must order: beef liver sashimi, pork ear robata, cold green tea soba with poached egg."

Lotus of Siam: The most famous Thai restaurant in the Americas, located in a strip mall, is renowned for its vast menu, which ranges from recognizable chicken satays to potent, well-spiced northern Thai dishes.

Bund Shanghai: Momofuku's David Chang loves this pan-Chinese restaurant. Among the things he picks out on the picture menu: soup dumplings, pan-fried buns, spicy fish hot pot. And "if I'm dining with my less adventurous white friends, a plate of sweet-and-sour chicken."

Other Mama: Favored by Carbone's Mario Carbone, Other Mama has terrific craft cocktails, like the Geraldine with bourbon and grilled pineapple, plus plenty of raw seafood, from oysters to octopus-habanero ceviche.

The Halal Guys: This summer, the famed street food cart that started in midtown Manhattan — the cause of lines that can stretch down the block — opened in Vegas on Spring Mountain Road. From 10 a.m. to 4 a.m., Halal Guys offer sublime chicken and gyro platters and sandwiches with the option of their mouth-burning hot sauce.