Rock and hard spot

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?

Here's my philosophy... If I have the money to buy the best, then I do it. In the case of the 70-200, I bought the Mark II because I was able to sell off some of my old gear that I wasn't using much anymore and one lens that the 70-200 replaced. I also bought it refurb from Canon and saved $500. I've heard nothing but absolute rave reviews on this lens and I knew if I didn't have it, I would always be wondering how much better my shots could be with it. So now I don't have to worry about that anymore. I bought the 2X extender as well for those rare times when the extra reach is needed. I think if you're a bird photog or something like that then you need a dedicated 400 or 500 prime, but for the occasional reach, I think the extender is fine.

I vote you go 70-200 2.8 IS with the extender!

The 70-200mm and 100-400mm are completely different lenses, and they perform differently on different formats. You can add a teleconverter to the 70-200 and do pretty well, although I think some people say it's not as good as the bare 100-400mm combination (though IS should still be better), but at that point you are looking at a price almost double that of the 100-400mm, if you buy a new EF 2X III extender.

I have been promoting this lens a lot, but another option that is only somewhat more expensive than the 70-200mm f/2.8 is the Sigma 120-300mm f/2.8. It can be rented online if you're unsure. It's a heavy lens, but with a teleconverter I think it's more suited for bird photography than the 100-400mm since you get an effective 600mm f/5.6 lens. On the other hand, the 70-200mm will do great at your average "zoo distance" from medium to large animals. Small birds, though - forget it. Even the 400mm focal length feels far too short for the smallest birds, even on APS-C, even nearly within feather-pulling distances.

The question you should ask yourself at this point is - what will one lens or the other do for me?

70-200 f2.8 II with the TC2III is pretty amazing. It's not going to give you the same IQ as the 400 f5.6 wide open (I've got both), but stopped down 2/3 and it's pretty nice.

I'm selling my 400 cause I'm not using it, but it's certainly is lighter than the 70-200.