Awesome
noflash - chrome extension
Speed up your browsing disabling not only flash, but any heavy object element that may slow down the page load and rendering (pdf, ads, etc).
Re-enabling
These objects (flash, pdf, etc) will be replaced with a button you can click to load the original stuff anytime you want while seeing the page.
White List
Edit your personal white list of sites to always allow flash, pdf, etc. Nice defaults are included: youtube.com, google.com, facebook.com, vimeo.com.