Skull candy noise cancellation have worked great for me. Could here them just fine at freeway speeds with a half helmet. I'm not sure I could have survived Nevada without them.
Not sure if it's been mentioned yet but I use a set of earbuds that have a volume control on the cord itself. It really comes in handy that way if I ever have to adjust the volume I don't have to bother with fumbling with my phone to get it out of my pocket/jacket. Just a thought.
I use skullcandy titans. They work great and let you hear enough so that you can listen to music and still be able to notice things around you. I use them both when I ride and when in a blackhawk or chinook.