Should I have bought two 24-105mm f4 L lenses

I can see the benefits of having one full frame body (especially for landscapes), and one crop body (especially for wildlife), and combined with the lenses you already have, would give you a really decent range (without having to resort to an EF-S 10-22) from 17mm through to 640mm (35mm equiv on your 20D).

Because I haven't used (or seen or touched) a 5D, I don't know how close the controls are to a 20D, but I get the impression they are very similar if not the same, so moving from one body to the other shouldn't be a problem.

With regards to the lenses - if you need / want two 24-105 is that such an issue? I know a lot of people will be saying to get a different lens, but if you are already covering all the focal lengths you need, then surely you're better off getting the lens you really need. What would be the point of getting a 24-70 when the range it covers is covered by the 24-105 anyway?

Anyway, hope that is helpful in some kind of way .

Goatee - the 5D seems to be like the 20D's big brother, same controls, you could move from one to the other with no trouble at all. It's just a little bigger. Maybe more than a bit.

Sounds pretty good then. . . it could be that I've read about people having issues using a 20D as a backup to a 1 series body, where the controls are different.