There are two connectors for the Motherboard: 1-2 plugs on each video card depending on the type, haven't had experience with sound cards so not sure but doubt it (also, question do you work with audio in some way? b/c otherwise absolutely no reason to even get a sound card, you won't hear a difference between it and the mobo integrated sound), 1 for the DVD drive and 1 for each HDD. And it's more like the PSU plugs into them than vice versa. But don't worry there will be more than enough cables included with the PSU.
Also, there is a great reads in this forum if you haven't looked yet:http://www.tomshardware.com/forum/forum-31.html.
I also suggest you run this build by the same forum, can get a lot of positive feedback on how the parts are and maybe suggestions on how you can improve this build.