[Big Kahuna]

I've got an AGVSport AeroMesh Jacket and I love it. It's even been through a low speed off with no visible damage. It may be the lightest most air vented summer jacket on the market with CE armor and windproof/waterproof removable liner included.

More info here:

http://www.streetbikereview.com/sbr_reviews/sbr_reviews_agvsport-aeromesh.shtml