I currently own a 7D/gripped and am contemplating a return of sorts to the 1D series. I hope a few 1DS and 1DS MII owners can help with their advice.
First I don't find myself shooting sports as much as I used to and tend to shoot more portraits and landscapes. While the high iso capability is nice to have on the 7D, I find myself shooting more in the 100-200 iso range with my flashes when taking pics of the children and grandchildren.
Now I had contemplated a 5D but I have been spoiled at how easily a 1D series can lock focus and track moving objects, meaning grandchildren in this case. Otherwise a 5D more than holds its own in IQ against either of the other FF's I mentioned.
I currently own a 35mm f/2, 50mm f/1.8 MII, and 85mm f/1.8 and will either add a 24-105mm f/4 or 135L soon.
I should also mention I have owned a 1D Classic and 1D MII so I know how they function and feel in my hands.