As the 460SE needs 25A of current and your +12V rails are 18A each you have that covered (you'll be plugging in 2 X 6 pin connectors into the video card - ensure each 6 pin connector comes from a different +12V rail).
The power connecter connected to your motherboard (the 4 pin one in the picture) is additional power for the CPU. The Crosshair V Formula has another 4 pin molex connector for even more additional power to the GPUs
The power supply you have chosen looks more than adequate
