While doing all my research on lenses I decided I should get a fast tele lens in order to get some good sport shots at night. The lens I have decided to get is of course the EF 70-200mm f/2.8L. My question is the IS model worth the extra ~$560? (Using B&H's USA Price) My main use of this lens will be sports but I will also be doing some nature and hopefully some animals. For the sports shots I will always use a Monopod and for the nature shots I will more than likely use a tripod. But there might be a time where a furry little creature runs out in front of me and I do some hand held shots. I'm saving for this lens so I wont get it for a while but I want to be sure which model I am getting. Also don't know if this helps or not but I'm asking for a EF 400mm f/5.6L USM for my Birthday and Christmas present so with luck I will have it in November. Its main use will also be nature and sports (Track mainly). I have only looked at Canon so if you know any fast lenses that would work for me that would help too. Trying to keep it under $2000. Thanks for your help.