Panasonic Lumix Lens 12-35mm f/2.8 - $850

This is one of the best lenses for the micro 4/3 camera system. It features POWER O.I.S. image stabilization, nearly silent operation when shooting video, and specially treated glass that dramatically reduces ghosting and flare. A splash-proof and dust-proof design means you won't need to handle this lens with kid gloves, or put your camera away when a drop of rain falls. This lightweight (10.8 oz) lens is also compact (2.9x2.7") and has a sturdy build quality, with a durable metal mount.

I sell it only because I am moving to a DSLR system and can't afford to have both. The lens is in an excellent condition (scratch free). I am happy to show it for testing at a local cafe (Stanford/Palo Alto area).