Ahh, open cockpit, pottering arround the sky, wind in your hair...
I suspect that the "wind in your hair" effect is lost with a helmet. I currently use a custom made low noise headset with noise cancelling mic.
Longer term I'm looking at the ear inserts available similar to what the police use. They are moulded for your ear and give much better (passive) noise cancellation without the bulky headset round the outside.
If anybody has experience of them I'd be grateful for some gen....