Rounded cables can help to tidy your case up and improove airflow. They also look nicer if you have a see-through window case.
At Overclockers they have the cables listed so you can't go wrong
HERE
As for your graphics card..... You won't need any drivers to begin with. It will run at its default mode and windows will install with basic rtesolution anyway.
Once you have Windows installed, Then you can install the graphics drivers.