I am looking to expand my gear since I want to start doing more than just automotive for now. I want to expand into weddings next year as well. Glass aside, I need another body. Not as a back up but something I can use in tandem with my 6D. Since I love to shoot primes (will be buying more) I'd love to switch cameras without compromise. I initially considered 7D, another 6D, 5D2, 5Dc.
7D: Great camera, but the ISO limitation are strongly discouraging me from going this route. I just wouldn't feel comfortable shooting a wedding with this especially since last wedding I was 99% of the time over ISO 1600 anyway.
6D: Can be found at quite a good price, even brand new. $1600 or so is fantastic, considering I spent $1800 here in Canada a year ago and that was when it was on sale as well, so easily saved $250 or so.
5D2: can be found for a great price, but I need to buy CF cards again. Used to own this before the 6D and loved it. Fantastic camera.
5Dc: produces amazing images for the age of the body. Only reservations are slow CF support and horrendous back screen. Also no easy pad or stick to change AF points, and no ISO button on top of the camera.
As of now, I'm leaning towards the 6D as I can have the same body and seamlessly switch bodies, especially when shooting 2 primes and don't want to fidget with settings. I considered 7D2 as a wild card, but with all the speculation I just can't reliably consider it unless its released soon at Photokina.
My long term plan would be to shoot dual 6Ds for a year or 2 then upgrade to new 5D3 or 5D4 when that comes out, add a 7D in the mean time as price is always plummeting.