I stepped up to the 1DS3 from a 5D and I strongly believe that the 5D is still an amazing camera. If the 5D had more pixels, for cropping, I may have waited for the update to it.
the 1DS3, however, does give me that head room to crop nicely when needed, such as on people portraits,. I crop very little on landscape and otehr types of photography because I'm able to take my time and compose just as I want. too, doing people photography in a fast paced situation means you can get a wider shot, say 3/4, but when you crop in you may have a very nice head shot--and still have 240ppi at 9x12. Very nice!
But back to your problem. I too put my vote in for the 5d, unless you need a sealed camera. It's nice. Very nice.