I *highly* recommend, for everyone, a buckwheat pillow.
It 'breathes', absorbs sweat (the head sweats a *lot*) and does not attract mites or bacteria. It's made of the inert hulls of buckwheat and has been used for centuries in Japan.
Once you try one of these, that's all you'll ever need.
The size that works best is smallish-- a rectangle or a cylindrical shape that basically fits under the neck. It also tends to align the spine whereas many problems are created by (standard) pillows.
best is probably one of those old carved wood stands that support the back of the head (you can sometimes find in Africa) but since we likely don't have access, and are too "coddled" as mh would say, to be able to handle that--the buckwheat pillow is perfect.)
don't be fooled into thinking bigger is better though. It's not.
If you buy a regular pillow sized buckwheat pillow, you'll end up needing to split it and make two.
Those who can sew can make their own, and just buy the organic buckwheat hulls.
Martha stewart has some great instructions and a downloadable pattern for a small and ingenious reading pillow if you search for "buckwheat pillow" on her site.
okay, never mind searching...
here are two links:
Rectangular pillow instructions:
http://www.marthastewart.com/page.jhtml?type=content&id=tvs1474&con...
hourglass shaped neckroll:
http://www.marthastewart.com/page.jhtml?type=content&id=tvs6528&con...
and for bulk organic buckwheat hulls:
http://www.buckwheatpillows.biz/bulkhulls.html
P.S. If anyone finds a chaeaper (but still organic)source, please post it!