Second body quandary: Pls help!
OK, a little background: I guess you could say I'm back in the amateur ranks having shot professionally for about 35 yrs. My principal photography is flight photography: air shows and raptors although I shoot almost anything that catches my eye and I usually shoot everything at ISO 400 occasionally straying up into 640 or 800. I will sometimes print my best work at home up to 13x19 using a Canon Pixma Pro9000, and I'm pretty anal about color calibration between computer and printer.
My current camera is a 40D which I adore. I'm in the process of trading in my 300 f2.8L IS towards a 400mm f4 IS DO. I'd like to add a second body and I have about $1200 to spend. As I see it, my options are: add another 40D which I'm already very comfortable with, and bank the difference; purchase a pre-owned 1D MkII or MkIIN, which would give me faster AF acquisition, faster fps, and the ability to AF at f8, or purchase a new 50D. My quandary is finding a decent 1D MkII or MkIIN with a low shutter count that's in good shape, the learning curve involved in learning a brand new piece of gear, and the slight loss of crop factor of 1.3x down from the 40D's 1.6. The Series 1 camera will give me the ability to AF at f8 but I'm trying to be realisitc when thinking that having the ability to have a decent 800mm f8 with AF just isn't that important. The final option is to add a 50D but is having some new bells and whistles like lens micro-adjust and an increase in pixel density that much more worth it. I've read from a number of sources that the 50D performance at ISO 400 is not as good as the 40D and that's of primary concern. Right now, I'm leaning towards just getting a 40D for now....
I'm looking forward to your suggestions and opinions!