Jane,
I would not sell it so fast because of the fine focus even at small apertures and the ability to grab things where the 5D and others struggle. Furthermore, the thing is full size so wide lenses are wide, which allows for better landscape and architecture.
The camera will go down in value as soon as the Canon 1D II Mark III hits the market in weeks when it shouldn't because I think that for much use the 1DIII may be a yawn, (not for me as I like shooting in dim light with wide open lenses.
We discard a camera after 8-16 months like lovers who we have gotten used to or who leave the toilet seat up or steal the toothpaste or don't do something else quite right. Still you have your 1DII and that is a stalwart friend who will go with you through wind and rain and even at a pinch stop bullets for you.
It's a fine camera, the 1DsMark II and it will stand so for the next 5-10 years. Stillm, if you like tradinng, there's money for a superb lens, great dinners, Bordeaux wine approved by Nicolas and a vacation to boot!
Asher