Good point Stetson, I was just doing some reading on the F4 and that is a better choice...you just saved me some money!!! I maybe able to squeeze in that 100 macro too
That does seem like the correct choice in your case. The 70-200/2.8 is for the most part a photojournalist and wedding/event type lens, not necessarily a nature/wildlife lens. Sure it would work great, but at dusk and dawn and at that range of focal lengths the extra stop is probably not that valuable since it's able to be handheld to ridiculously slow shutter speeds.
Go that way, you'll be better off.
