I'm in the process of preparing for an upcoming trip and I'm going back and forth between the EF 200mm f/2.8L II USM and EF 70-200mm f/2.8L IS II USM as the telephoto lens to purchase to bring along for the trip, although the EF 70-300mm f/4-5.6 IS USM has currently caught my eye as a lower cost option. Right now I'm anticipating that most of my photography will be done with either a EF 17-40mm f/4L USM or EF 50mm f/1.4 USM, although I do have a EF 28-135mm f/3.5-5.6 IS USM at my disposal as well, the Canon 40d is my current main camera although I have been contemplating an upgrade at some point in the future so I generally sly away from the EF-S lenses.
In order to save weight and space, I am trying to limit my selection of lenses to one wide-angle lens and one telephoto lens with the 50mm f/1.4 being added in due to it's compact size in my kit. The last time I traveled I did miss out on a couple shots due to not having a sufficient telephoto lens with (was traveling with the 17-40mm and 28-135mm); however, the vast majority of my photographs were taken with the 17-40mm. Quite a bit of my photography will likely be in dusk or night time conditions as I will be attempting to capture the aurora borealis which is another reason that I don't anticipate heavy usage of the telephoto lens.
What would be some recommendations in this situation?