Of all pillow types, latex foam pillows come the closest to garnering an expert consensus (though there are some folks who simply don't like, or are allergic to this material). The most convincing endorsement comes from Dr. Paul Bacon, interviewed by The Boston Globe, who says years of research into the "perfect pillow" have led him to favor latex/cotton combination pillows. One reliable source, SleepLikeTheDead.com (which bases its reviews on reports from actual users), recommends latex pillows for their superior neck support, air flow, durability and resistance to clumping or flattening.
Latex pillows are filled with latex foam, which is derived from rubber, a natural plant-based substance. As SleepLikeTheDead.com says, the foamy interior ventilates better than other pillow fillings (notably down and memory foam) and retains its shape in a reliably rubbery way. Another option is to buy pillows filled with shredded rubber; reviewers say these pillows are (no surprise) extremely springy and durable, and offer just as good support as latex pillows.
Latex foam and rubber pillows do have one significant downside: When they're brand new, they can emit an odor for days or weeks; some describe it as a slightly sweet smell. If you're a very sensitive sleeper, this consideration alone may lead you to entertain other highly rated pillow fillings, like buckwheat, cotton or wool. From what we've read, though, the initial odor generally dissipates, of you can try using a tight-weave pillow cover.
We've read conflicting information about the susceptibility of latex foam and shredded rubber pillows to dust mites, which can cause allergic reactions or trigger asthma attacks in some sensitive individuals. If you're concerned about this, check the manufacturer's claims carefully before buying your pillow.