Interesting . . . I've had the 5D and 1D Mk II at the same time, and they like apples and oranges. 5D for high iso needs, going wide, more resolution, and ability to travel "light"; and the 1D Mk II for events, sports, and anything action-oriented. I eventually sold the 1d Mk II because I realized I wasn't shooting that much action stuff, and downgraded to a 1D Mk I - the classic.
I loved the detail and colors from the 5D for portrait work. Unless its AF isn't keeping up with your needs, I'd say the 5D is the keeper for these tasks. However, I wouldn't feel much loss if I had to keep the 1D Mk II either.