Thanks for the help!

Have decided to either go for the 70-300mm L IS or the 100-400mm L IS for telephoto - which produces better images?

The general consensus seems to be that the 70-300mm is better with the more up-to-date technology and IS and generally produces better images, faster. Is this entirely true?

I am guessing that canon will announce a replacement for the 100-400mm in February? hopefully along with a new '650d' with the new processor!!