Best Down-Filled

Cuddledown Primary Comforter, $169 for queen in Level I (meant for year-round use)
If You're Looking for: A lightweight comforter that will keep you toasty.
Why We Like It: This plush comforter, handmade in Cuddledown's Maine factory, is filled with European duck down that has a quality 600 fill power. (The higher the number, the lighter, fluffier, and warmer the down will be; look for a fill power of at least 550.) The down clusters won't shift around, because the sewn-through box stitching keeps them in place, and they won't escape, because the cotton shell is downproof.
To Buy: 800-323-6793, www.cuddledown.com

Best Wool-Filled

Merino Wool Comforter, $129 for full/queen
If You're Looking for: An insulating comforter that's weightier than down and lets you feel as if you're nestling under layers of blankets.
Why We Like It: This medium-weight comforter is filled with soft merino wool and covered by an unbleached cotton shell. Wool is the most effective fiber for wicking moisture away from your body, so you don't wake up feeling clammy. A wool comforter will keep you cozy during the winter months, even if you sleep with the windows cracked open. But unless you really crank up the A/C, "it's too warm for summer sleeping," said one tester.
To Buy: Gaiam, 800-869-3603, www.gaiam.com.

Best Cotton-Filled

Garnet Hill Prestige All-Natural Cotton Comforter, $178 for double/queen
If You're Looking for: A medium-weight comforter that's not too warm.
Why We Like It: One hundred percent cotton through and through, this comforter is breathable and feels more substantial in weight than silk, the other warm-weather option. But since cotton is not as insulating as wool or down, you can use it only in warmer months or temperate climates. It's especially good for people who get hot easily but need more than a thin blanket over them at night.
To Buy: 800-622-6216, www.garnethill.com.

Best Synthetic-Down-Filled

Primaloft 400-Thread-Cotton Sateen Comforter, $200 for queen
If You're Looking for: An easy-to-wash comforter that's lightweight and warm like down and also hypoallergenic.
Why We Like It: Comforters made with synthetic down work well for allergy-sensitive sleepers. Unlike down comforters, which can be tricky to launder, PrimaLoft comforters are simple to machine-wash. (PrimaLoft was developed for the U.S. Army, which wanted a synthetic fiber for its sleeping bags and apparel that mimicked down's softness and insulating qualities but did not absorb water.) Use this comforter as a low-maintenance solution for beds with kids, pets, or sleepers who prefer not to use protective comforter covers. The plushness feels similar to that of down, and one tester found sleeping with it "heavenly."
To Buy: Bed Bath & Beyond, www.bedbathandbeyond.com.

For Couples Only
If you want a single comforter that will satisfy two sleepers who have different definitions of "warm" and "cozy," you can customize any of Cuddledown's down comforters by choosing two different warmth levels to match your and your partner's respective sleep preferences. The comforter will be shipped to you as two halves that hook together with cuff links.
To Buy: Dual Warmth Sleeping System, 800-323-6793 or www.cuddledown.com. Call for pricing, which depends on the size of your bed and the fill level of each half.

Cover Story
A comforter's protective cover is supposed to make washing, and your life, easier. But when you're struggling to get the blasted thing back on, you may not think so. Bedding experts agree that the easiest way to put on a comforter cover — be it a twin or a king size — is to start by turning the cover inside out and laying it on top of the comforter. Then grab the bottom corners and pull the comforter through. Clipping the four corners with comforter clips (shown above, $8 for set of four, Cuddledown, 800-323-6793), which remain inside the cover, makes the process even easier.