TheBigDog wrote in post #14528463
Even though I have 2 bodies I don't really consider one or the other the "backup". Depending on what I'm going to be shooting I choose which body is going to be better, action/sports I'm pulling out the 7d, portraits or macro I'm gonna grab the 5d mark 2. They both get used enough that they never get jealous

Yeah, I'm the same (although with a 40D / 5Dc combo).
For sports, action, birding, etc. the 40D is my "prime" with the 5D as backup and for portraits, landscapes, etc. etc. the 5D is prime and the 40D is backup.
However, in most situations both cameras will still be in use, as I will fit them with different lenses and carry both ready for action. Saves a lot of fannying around swapping lenses if the two most likely to be used are already mounted.
A common combo I use is the 100-400L on one body and the 300 f/2.8L on the other (possibly with a 1.4x or 2x TC on it). That way when something happens where the prime is the wrong length, I just drop that camera and pick up the one with the zoom on, ready to go.
Dan, I think you are missing out by leaving the 50D in it's box. It has abilities in some areas that the 5D doesn't and can be the better tool for some jobs. I don't know if you would benefit from carrying two bodies at once, as I don't know how many lenses you have, but if you get fed up swapping lenses at events, when you need a different focal length, it is well worth carrying both.
In the film days I would carry 3 cameras usually, when I first went digital I found it soooo frustrating to be constantly switching lenses at some events with only having the one body at first. When I upgraded to the 5D, it never crossed my mind to leave the other body (then a 20D, the 40D came later) behind, I was always going to use both.