I have found that for me using a wireless, bluetooth intercom system was the way to go. There are a raft of units in the marketplace and I have supplied a link that is a great resource for research on the different units out there:
http://www.webbikeworld.com/motorcycle-intercoms/
I purchased the Sena SMHB-10 unit from Revzilla and have found its functionality and ease of use to be excellent. Conversations with my passenger are easy to initiate with the large dial and the transmission is crystal clear at highway speeds. I also like to be able to hear my GPS instructions through my headset and be able to make and receive handsfree phone calls when paired with my Zumo.
All this being said, if you need a CB as well, then purchasing the BRP com system is the way to go.