Eric,
One common "musician's earplug" is the Westone ES49 -- search for them at
www.westone.com. They do require that you have molds taken of your ears, but I have found two audiologists over the years to do that by simply looking in the yellow pages.
The Westones work fine as long as you're in a playing situation where you can hear yourself. They do take some getting used to -- the sound that you hear will be radically different. Some players have also reported that the musicians earplugs also threw off their sense of pitch, though I never noticed that (or nobody I play with has ever told me).