And there's something for everyone: briefs, boxer briefs, trunks and cycle shorts for men - bikinis, thongs, hipsters and boy shorts for women. And it's not just the style, it's the fabric too - everything from nylon and lycra to pima cotton and microfiber.
Forget the bottom of the hamper. Underwear is top drawer.
Rebecca Apsan is what you would call a connoisseur of lingerie. For 27 years, she's been selling some of the sexiest underwear in her downtown Manhattan boutique, La Petite Coquette.
Aspan says boy shorts are hot right now in women's underwear. "These have taken not the place of thongs but they've been selling very, very well," she says.
"It's the closest thing to your skin, and when you're wearing beautiful underwear or silk underwear, you walk differently. You feel sexier. You look sexier," says Apsan. "It's very, very important to wear beautiful underwear under whatever you're wearing. Even in the gym."
"Even at home cleaning the kitchen floor?" Brzezinski asks.
"Absolutely. That's the best. You might get very, very lucky," laughs Apsan.
In fact, more and more Americans are having fun with their underwear styles, with so many to choose from. According to a recent survey, 52 percent of women prefer the panty; 31 percent prefer that arguably uncomfortable skimpy thing called the thong. But sexy, out-there underwear is not just for women anymore.
"Men's underwear is just really a whole new scene. It's not just your white, tighty-whities anymore," says Mike Tawil, president of 2(x)ist, one of the more successful new brands of designer underwear.
His brand is worn by the likes of pop star Justin Timberlake, R&B star Usher, and even socialite Paris Hilton.
"The new look is making sure it fits well," says Tawil. "That it's comfortable. We'll go everything from a thong on one end to a boxer brief on the other end."
"And a lot of men will be wearing thongs, and wearing them now. You can't believe the numbers that we sell in those. It's really wild," says Tawil.
Simon Doonan, creative director at Barney's New York, says, "I know some really strange men and none of them are wearing leopard skin thongs."
"They don't go and think for hours, 'Shall I buy a jock strap with support in it.' They just go and replenish their underwear. And they tend to buy the same ones," he says. "Most men are either boxers or briefs. It's Republican or Democrat. You know, it's just very simple."
Underwear certainly has come a long way. Who can forget Tom Cruise in his briefs in "Risky Business," Madonna wearing Gaultier's corset bra on stage, or Victoria's Secret models on the runway?
In short, underwear is everywhere, and it's never been more in style.
Kim Vernon, of Calvin Klein, says they set the trend, starting with Olympic pole-vaulter Tom Hintnaus, actor Mark Wahlberg, and today, British soccer star Freddie Ljungberg.
"Underwear is a part of the outfit for a woman. Very much a part of the outfit," says Vernon. "I think men are starting to catch up."
"The premise isn't 'Sex sells.' 'Let's push sex and underwear.' It's generally a guy by himself. I think the issue is you want to look good, and feel good and this product helps you do it," she says. "And I think we made that OK... you can have a guy standing in his underwear and it's hot. It's not wrong, it's not dirty, It's hot."
Maybe. But as Rebecca Apsan sees it - underneath it all - sometimes what's really sexy isn't what you see, but what's left to the imagination.
"The mystery is gone. People are showing too much. It's always so much sexier to show a hidden, like if you're wearing a white bra and a white shirt and you had a little peeking of a little lace coming through, that is sexy," says Aspan.
So go ahead and treat yourself to that new thong you've been eyeing, break out a new pair of boxers, and don't be shy about it. Underwear is the one thing we all wear, unless you don't wear anything at all.