Earplugs are a very personal thing, like helmets. What works for you works for you... but may not work for others.
Like others I've tried multiple styles. My biggest beef with a lot of foam plugs is that they're often too soft and wind up just mashing into my ear rather than getting fully into the ear canal before expanding.
Give the wax ones a try... good for a few uses before they get too grungy. Basically it's a blob of wax that you push into your ear... it molds precisely.
Somewhat OT since they're not earplugs per se, but on the road I use and absolutely love my PlugUp S-plug earbuds. Totally comfortable and they disappear into your ear canal so no hot spots from the helmet. Isolation is superb so any audio I listen to can be kept at a reasonably low volume. I've also used these as straight earplugs... they're that good.
http://www.plugup.com/the_S_plug_ste...rbuds_s/67.htm
