Update: The extension can be downloaded from the official extensions gallery. You will need a linux or windows chrome beta for extensions to work.
Flashblock and ClickToFlash has been hugely popular for Firefox and Safari respectively. Flash on windows is (mostly) a nice piece of software. But on mac, Adobe hasn't optimized the flash runtime and watching a video or visiting a page with flash ads can push your CPU usage to 100% which is very annoying.
I have made google chrome for mac my default browser for a week and the lack of a flash blocker has been bugging me ever since. So I ported over this ClickToFlash Jetpack to chrome. Thankfully chrome for mac has enough extension support to make this work. Install Kill-Flash and enjoy a flash free browsing experience. Like other flash blockers, Kill-Flash replaces the flash element with a clickable area (shown below). On clicking the area, the original flash ad/video will be shown. You need to be using Chrome Dev Channel for this extension to work. I have tested it only on mac (the latest mac dev channel build 126.96.36.199 disabled extensions. So no longer working on mac) but it should work fine on windows chrome too.By default GMail and Youtube has been whitelisted.
Due to the way chrome extensions work, it is not possible to stop the download of all flash elements. There is no hook "give me the DOM before anything has been downloaded". The bigger flash elements and videos will probably not get downloaded depending upon your network speed. A huge "Thank You" to the author of the jetpack Thomas(French Site) Saved me a ton of time!