6D or 5D Mark III if you can afford it. I got my 5D3 for $2600. Keep on the lookout for deals. If you can afford it, keep your 7D and 17-55. You'll miss it if you sell it. If your 18-135 is the first edition, sell it or give it away. It's a piece of crap, for lack of a better description. Actually if there was a EF mount on a real piece of crap, it might take better photos. Obviously, you know that already, since you don't use it anymore.