The old-fashioned crank-style popper wins hands-down (try the Whirley-Pop six-quart hand-cranked stovetop popcorn popper, $30, amazon.com). It's easy to use and to clean, and within minutes it makes popcorn that is fluffy and crispy, not chewy. You need to use only about one tablespoon of oil to make a full batch of popcorn (four to six quarts), so it's also low in fat. If you want no fat, air poppers are the right choice. Fireplace poppers have a high romance quotient but tend to burn both kernels and popped corn. (Smoked salmon is one thing; smoked popcorn is another.) Whatever popper you use, keep popped corn crisp by uncovering the pan as soon as the popping stops. Then the escaping moisture won't settle back on the corn and make it soggy.
Coconut or palm oil gives you the taste of movie popcorn, since those cholesterol-raising oils are what theaters used exclusively until 1994. That's when the Center for Science in the Public Interest blew the lid on the movie corn's fat content―about 80 grams of fat for a large tub. For something less artery-clogging, try canola oil. Its mild, clean taste doesn't overwhelm popcorn's natural flavor, and it has a medium to high smoking point, so there's little chance of scorching. It's also inexpensive. Most important, canola oil is low in saturated fat and high in monosaturated fat, which helps reduce levels of (bad) LDL cholesterol. You might want to try olive oil, a nutritional equivalent of canola oil, because it is high in good monosaturated fat and gives popcorn a richer flavor, but olive oil has a low smoking point and tends to burn quickly. Corn and other vegetable oils don't offer the same nutritional advantages as olive or canola.
No matter how much or how little the stovetop kernels cost per pound, Real Simple testers were hard pressed to tell much of a difference in taste among the most popular brands. (All kernels tested were cooked in the crank popper with 1 tablespoon of oil per 1/2 cup of kernels.) But with its crispy, delicate texture, popcorn made from Newman's Own kernels was slightly ahead of the pack. Arrowhead Mills' organic kernels had the strongest corn flavor but weren't as crispy as Newman's Own.