So with the year quickly coming to an end I'm starting to get a little more excited knowing that soon I will have my tax return in hand and headed to the local camera shop. With that being said I'm faced with what lens to get? My thoughts are a used 70-200 2.8 IS or a 100-400 used or new. I really want to be able to get that sweet bokeh and think that I would use the 70-200 more since I very seldom get to go anywhere to get some awesome animal shots, but at the same time I really don't want to get caught with my pants down either if I happen to go to Yellowstone or somewhere else where I'd need that reach. I'm pretty close to Yellowstone, so the chances of going up there are pretty good and think now that more of my friends are getting into this hobby we'll be going more often. So here are my questions. Should I just get the 200 and a extender? What's with the date codes and what should I be looking for? Will the 2X extender give me the same results as a 400? What's the difference in the 70-200 1 and 2? I'm pretty sure I'll have money left over for the 2, but is it really that much better?