I'd recommend the Evga 680I
board. All the bells and whistles plus comes with a lifetime gaurantee on overclocking. Meaning if you fry your board overclocking send it back and a get a new one free of charge
I also love the digital bios lcd for error codes. No more listening for beeps if something happens it will show you the error code on the lcd. Support for quad cores and 3 PCI-E X16 slots. Although if i'm not mistaken the center slot runs 8X could be wrong though. I dunna no I don't use it yet.
Great overclocking board. Bios settings from wall to wall you'll have alot of fun with this board.
O and about the top case mounted USB's thats a simple as plugging them into the boards secondary USB inputs on the motherboard. Your case should come with a blue usb plug that you plug into the end of the wire from your case. That mates with the USB on board.