I have just completed a two day ride and tested these new ear plugs. The verdict - THEY ARE FANTASTIC.
http://www.alpine.nl/EN/consumer_motor.htm
Not only are they comfortable and very clever, but they work.
They are a simple but clever design based on a reasonably standard double baffle configuration but they also use an insert/filter that is attenuated to the range of noise associated with wind in the helmet. What this would appear to do is block out most of the wind noise without significantly reducing the other sounds associated with riding.
Using these I am now able to chat over Bluetooth communicator with my wife (bike to bike) at speeds of up to 120km / hour comfortably and still hear my engine and other road noises. Without them we would give up at anything over 90). When parked (helmet on) I can have a normal conversation with people around me also.
The product comes with two types of insert and the rider can swapped them over for a different attenuation level if you intend to do longer higher speed riding.
These are very, very clever and very very comfortable. They make using an intercom, mobile/cell phone or MP3 player possible at speed.
I am in Australia and they are in the Netherlands so I purchased them from New Zealand - closest reseller.
Don't you just love the internet and on-line sales. Not cheap - almost AU$100 for two sets delivered but worth every cent.