I just treated myself to some custom plugs. Nothing worse than bad fitting plugs or struggling to get them in. Usually if they're fiddly you are tempted to go without them and that way leads to hearing damage. You'll find loads of info saying 15 mins at 90mph is the same as a day in a sawmill and other entirely un provable "facts" Quite expensive at about £50 but dead comfy.
http://www.ultimateear.com/products_motorbike.html