Well, there are plenty of earbud reviews on Head-Fi. The Sennheiser MX580 is pretty terrific sound quality wise. I would be willing to sell you my unused pair or my Yuin PK3 (also terrific for sleeping) for a darn good price.
Nice recommendation, theleonlion! I forgot that Sennheiser makes a small line of ear buds. And on Amazon the MX580's aren't expensive at all(about $30).
As for the PL50's, those look like they might not be all that comfortable to sleep in. And where in the US are the 9Wave's sold? I can't find them or a price.
By the way, how is the sound quality of the MX580's? They gotta be a step up from stock ear buds, right(eventhough I think my stock Cowon buds sound way better than stock iPod buds)?
EDIT: Oh wait, what am I thinking? I have a pair of Sennheiser CX 300-II's that I thought sounded absolutely fantastic for the price. But I accidentally through them in a candle, and one side got doused with wax and no longer work. And since I don't have the receipt anymore(bought them in a store a couple years ago) I can't get them replaced. I'll pop those in and lay down and see how they fell. They don't portrude out of the ear really none at all. So as long as those feel ok then maybe I'll get another pair off of Amazon.
Anyone have any experience with the CX300-B's? They're only $30.