From what I've heard (pun intended), muffs protect the mastoid from sound and therefore are preferable to any "in-ear" device.
The best I've heard of is Peltor.
You might do a search on Peltor - we had a long thread some months ago that discussed many different brands.
Also, you might get a more thorough response in the Gear and Accessories forum.
[This message has been edited by Dennis (edited October 25, 1999).]