As a cooking instructor, students are constantly asking my advice on kitchen purchasing decisions. There are the gadget freaks (I prefer less clutter), those who refuse to spend a buck (a cheap dull knife really isn't better), those who don't like touching food (garlic press), and my favorite, the fat-phobes who believe it's possible to cook tasty food without fat and swear by their fat-free oils and nonstick pans. One of the most important kitchen investments a home cook can make is the skillet. Let's review the most popular options: nonstick, stainless, and cast-iron. Starting in the center of a controversial debate, let's take a look at the nonstick skillet. Teflon is the brand name of a thermoplastic fluoropolymer introduced by DuPont as a commercial product in 1946. It has the least friction of any known solid material, and is used primarily as a nonstick coating in applications as varied as kitchenware, armor-piercing "cop killer" bullets, the valves and seals in the pipes holding uranium in the Manhattan Project, and, less aggressively, to keep furniture, carpet, and clothing stain-free. Teflon has also become part of the common vernacular: "The Teflon President" (Ronald Regan) and "Teflon Don" (John Gotti). Teflon has recently come under scrutiny by the FDA and other watchdog groups for its ability to kill birds and create flu-like reactions in humans for up to one week when heated to high temperatures (500 degrees Fahrenheit and beyond). But this danger can be avoided by keeping your nonstick skillet below 500 degrees, the temperature necessary for a real good sear. Look, cooking is dangerous, and Teflon is sort of weird, but if used properly, it can be a good, reliable tool. If you're really worried, think about the old joke, where a patient tells his doctor: "It hurts when I do this." And the doctor replies, Then don't do that." Nonstick skillets are best to use when you are gently cooking an item over low or medium heat. Omelets, bacon, crepes and potato hash are perfect nonstick skillet candidates. If treated properly (no scratches, no burning, no scouring pad), the nonstick surface will work, and yes, your pancakes and frittatas will slide right out. But don't make yourself or your family crazy; assume that the skillet will scratch after a year or so; toss it and get another. After using, wipe your skillet clean with a kitchen towel, avoid soap, sponges and dishwashers. If you're stacking your skillets, place paper towels in between to avoid scratching. Make your big investment on a nice stainless skillet lined with aluminum or copper that has a good heavy bottom. Josh Grinker, chef/owner of Brooklyn restaurant Stone Park Cafe, says: "Our high-quality stainless pots, the good stuff with heavy bottoms, are lifetime purchases. If they can handle our commercial kitchen, they'll be fine in the home." Though Grinker loves his nonstick skillets for the omelet rush at brunch, he acknowledges they've got a shelf life of four to six months, maximum.