Definitely 7D for several reasons! Though 7D is not full frame camera like 5D Mark II, it IS a fast camera, offering 8fps continuous shooting, which will be useful in sports events. For still images it is still awesome, especially 19 point AF is I think the best among many consumer level DSLR. Since it's APS-C camera, it can take variety of lenses including EF-S, which offers variety of telephoto lens at affordable prices for nature shots. 7D's movie mode is excellent to where some films are TV shows are filmed by 7D. Its body is weather resistant, great for any weather on trip but you'll have to make sure that your lenses are weather resistant as well. Most of EF-S lenses are not particularly weather resistant. There's an upgrade firmware for 7D coming up in August, which will make 7D even more great camera overall. Here's the link to Canon's firmware upgrade information: http://www.usa.canon.com/cusa/consumer/standard_display/EOS7D_firmware
Hope this helps!
