The Canon line-up is obviously going through a massive shake-up this time and is causing big dilemmas for a lot of people!
1) 5D Mk II is an excellent camera but the AF system never compared to that of the 7D
2) 7D is a great camera with great AF and packed with features but the image quality isn't on par with the full frames
3) 6D has great features (a bit similar to the reaction seen for the 7D on its release) with its built in Wifi and GPS and wireless flash triggering, but they used the old focussing system from the 5D Mk II in it
4) 5D Mk III beats the image quality of the 5D II and the focussing system of the 7D but at a massive price premium, oh and even though it is £1000 more than the 6D, you have to bolt on those Wi-Fi and GPS modules
For me Wi-Fi doesn't bother me too much but GPS is a really nice feature to have, saying that I am not going to get a 6D just for that reason because I may as well get the 5D II (which should be with me shortly, look forward to comparing it to my 7D)
My perfect camera right about now would be the 5D Mk III with built in GPS