Graham and I use Collett Communicators (
http://www.collettcommunicators.com/). Had them since 1998 and have just gotten updated units this year. They are a bit finicky, but once you get them set, they work well. We do not travel the major highways very often, so wind noise is not too much of a problem.
Another system, The AutoCom, is designed for high speed motorcycle communication. We didn't want to be tied to the bike and the Collett's are self-contained, so no wires to plug or unplug.
The communicators have made a WORLD of difference in our enjoyment of riding together. We don't chat,

just use them to point out things or whatever.
We've used them with several different helmets as well, Nolan, Arrow, Shoei...