I just love love love IKEA's
ROLLEKA memory foam pillows. I tried one about 5 years ago and have never looked back.
I actually use it with the flat side up, not the curvy side. I change position often—usually sleeping on one side or the other, but sometimes on my back—and these pillows are the most comfortable I've ever used, no matter how I happen to be lying.
And because they're so compact, they're easy to take along when traveling. Which is a good thing, because everything else feels like a big mushy cartoon marshmallow to me now.
The cover is removable and washable. And they're only $15! My wife has a fancy $100 pillow, and there's no way I'd ever trade my ROLLEKA for it. Simply a great product, IMHO.