I'm surprised no one has mentioned the IRIS by 3DRobotics. It uses a brushless gimbal to provide the image stabilization and is made largely of plastic components that can be replaced easily. I have their hexa-copter (built from a kit) and have been very happy with it.

Two things worth pointing out that I think are very important:

* The IRIS uses RC plane blades so they are cheap to replaces

* The piloting software is open source