Upload & Sell: Off
I love the old 5D, I really do, I've had four and I still have one. I have probably earned more money with 5D's than any other dslr over the years.
But a good deal of the almost religious zeal which surrounds the 5D isn't deserved.
It was a fine full frame body in its day (read the only prosumer full frame body) and it has a pixel count which suited it's sensor size at the time. It's images are clean and clear with good colour and nice gradation of tone and of course the 'full frame effect' with fast lenses wide open. This was and is an attractive quality.
But it was and is slow in use, clunky with few modern features, a single reliable focusing point, no sensor cleaning, live view and a poor LCD. It is the VW beetle of dslr's, sturdy and reliable (when the mirror isn't falling off) and it will get you to your destination, but slowly and in modern terms, ponderously. It's almost a modern Rollei or Mamiya twin-lens reflex - it benefits from taking a bit of extra time. No bad thing.
The 7D might be a crop camera, but it's a crop camera with a massively improved (albeit crop) sensor and a great feature set. The 5D and 7D are completely different types of camera. Which one is better for you is really dependent on the type of shooter you are.
The comparative IQ isn't really a worthwhile way of choosing the model you need IMO
Religious zeal aside, I cannot imagine why one would want to buy an ancient (in tech terms) camera, rather than a more current one.
If full frame is very important to you (and I can certainly understand why it might be), you might consider getting a 5D2 from the Canon Loyalty Program. It's worth the wait for them to have it in stock; just call every day. It should cost around $1200 in the CLP, $1400 in the Canon refurb store.
The 7D is a fine camera (especially if you're shooting things that move), but its image quality is not quite up to the 5D2. That doesn't mean, by any stretch, that it's bad (just look at Imagemaster's photos), but in less expert hands (mine) I can tell a subtle difference (pre-processing) in the quality of the images between the 5D2 and the 7D.
Well when I upgraded my 5D's to 5D2's in about 2009 there was nothing, but nothing that I missed except smallish RAW file sizes and their impact on my computers.
It's great that the 5D has such a following, it keeps the resale value up and gives Canon a dslr 'classic', but honestly the 5DII is better in every way. The 5DIII is better still