Been meaning to shoot more with the 5D. Originally planned on using the 5D for street-shooting and interiors and have only taken a few N&W shots with it (because it is slow - both in FPS and the shutter response time due to the larger mirror).
But since my 300mm doesn't work with the 40D when I use extension tubes, I figured I better get used to using it. The IQ from the 5D has always impressed me; more so than any other body I've used so far. Good timing too as the insect life has been really slow to emerge this year and I finally had some good variety last night.
Some from yesterday. First 3 shots with the 300mm + 2x TC, the last 2 with the 300mm + extension tubes (can't remember what combination of tube lengths). Not a single glitch - unlike the 40D.