On which camera do you use the 70-200/2.8 II IS the most? That lens is still an option for me... bet again, it is heavy
When I used it on the friend's 7D it felt like an akward range - and I assume it feels more correct on the 5D2. Or?
Now that I have the 5D2, I use it most of the time for every situation except sports/action/wildlfe. IMO, the 7D and 70-200 really can't be beat except by a 1DMK4 for action. I think I would prefer the 70-200 over the 70-300 because it is faster and if you use it on a 5Dmk2 you have a lot of resolution to use for cropping that makes up for the shorter length of 200 versus 300.
As I said earlier with the 5Dmk2, I walk around most often with the 24-105. It would be perfect if it were a 2.8 but I am sure if that were the case, it would be close in weight to the 70-200 . . .
The 70-200 is a big lens I won't argue that. I use a black rapid "sniper" strap on my cameras which allows for the camera and lens to hang off my shoulder at my side instead of around my neck. It makes it a lot less obtrusive/easier to walk around with. I sometimes take the 70-200/5Dmk2 with me on short bike rides through the park with the kids and lock the strap so the camera sits at my back out of the way.
If you got a 5Dmk2 or 3 the 24-105 could take the place of the 16-35 I recommended earlier and as a bonus, you wouldn't have the gap between 35-70 requiring you to get a 50.