Yeah, so they expect the 5D-III to be available in summer 2012. Sounds believable. And so, I EXPECT that like the 5D Classic, and 5D-II, the 5D-III will premier at a premium price that many people will not be able to afford, such as $3199, to as low as, MAYBE, $2999. Canon will leave the price high at first; the 5D premiered at $3499, and those who could afford it bought it, then there were some rebates offered, bringing it down to $3199. Then, it sat there for a while. Then, the price was lowered to $2999. After about two years, it became possible to buy a 5D for $2,200 in a kit with the 24-105-L zoom, and selling off the zoom to get to the final price.
Fast forward...the 5D-II has been $2799 for much of its run. At various times, rebates have lowered the cost, and the MSRP has been lowered, then raised, then lowered. Right now, retailers are trying to clear the channel by offering the 5D-II at what is it? $2099?
You do not gain much by spending $2099 on a 5D-II versus spending $800-$900 on a used 5D. You're doing portraits. 12.8 MP of CLEAN, big pixels is all you need.
If you want to dump $2,700 into a "brand-new" camera, it might as well be a Nikon D700 or D800. Unless of course, the 5D-III adds a HUGE amount of new features, like TTL flash commander, high-FPS rate, professional build quality,top-class viewfinder system, 51-point AF system, and a built-in flash unit....all of which are available in a Nikon D700 today.
The original 5D offers about the same image quality as the original Nikon D3 or the Nikon D700, up to ISO 1600. The question I have is, "Will the 5D-III finally be a professionally-oriented BODY with pro-level features and sub-systems in it? Or will it continue to be yet another, third iteration of a $389 EOS Elan body, with a $1,800 sensor in it??" That is why Schwetty and I keep suggesting the 5D Classic, since your budget of $3,500 needs to give the MOST RETURN on each dollar invested!!!
And a fairly interesting article there on lenses:
Lens Genealogy « Canon Rumors