Do you really need something like 70-200/4 to pair with 24-120/4 VR? That's only 80mm extra. Just don't be fooled by cheaper and/or better Nikon bodies. Their lenses are more expensive.
Their lenses are NOT more expensive.
Just go check the prices...
Canon EF 70-200mm f/2.8L IS II USM - $200 cheaper than - Nikon AF-S Nikkor 70-200mm f/2.8G ED VR II
Canon EF 35mm f/1.4L USM - $300 cheaper than - Nikon AF-S Nikkor 35mm f/1.4G
Canon EF 16-35mm f/2.8 II USM - $200 cheaper than - Nikon AF-S Nikkor 17-35mm f/2.8D IF-ED
Canon EF 24-105mm f/4L IS USM - $350 cheaper than - Nikon AF-S Nikkor 24-120mm f/4G ED VR
Canon EF 24mm f/1.4L II USM - $350 cheaper than - Nikon AF-S NIKKOR 24mm f/1.4G ED
And that is mostly a listing of lenses what I think go with a 5DIII or 1DX based on price (if you can afford those you can afford the bodies). For a new entrant into the FF realm - to whom I think the 6D is aimed at - I think the following will be more representative (based on BH prices excl rebates and US model). I am leaving out 3rd party alternatives as it is available in both mounts.
Canon Nikon
17-40L - $740 None
24-105L - $970 ($800 kit) 24-120 - $1,300
70-200LF4 nonIS - $670 none
70-200LF4 IS - $1,350 none
100-400 - $1,700 80-400 - $1,680
28mm 1.8 - $510 28 1.8G - $700
50mm 1.4 - $400 50mm 1.4G - $440
300mm F4 IS - $1,350 300mm F4 IS - $1,370 (No VR)
430EXII - $300 SB-700 - $330
One can debate the ability of each item individually, but that doesn't take away from the fact that Canon as a whole is cheaper and
Nikon's lenses ARE MORE EXPENSIVE