Well, I'd just like the zoom to be there if I need it to be honest. At first I wanted it for portraits etc but it seems my 24-105L is actually doing well for it so I'm just looking for a lens for holidays for distant objects (ships, lighthouses, wildlife) etc. The extender is something I didn't actually think of, and you do make a very good point in regards to extending the reach etc, might have to give that one a look in