CS6 or the Extended version?
Unless you have interests beyond photography, probably not. Video is now in the standard version, although I don't know if the animation and keyframing is. There have been huge improvements in 3D that are extended only, and extended is also better for 32 bit / HDR.
The reason to get extended is if you are doing multimedia with other creative suite applications.
I am upgrading from cs5. Is there enough use in the extended version to pay the extra money?