Check this one Peter, looks ok 2x Sata3 ports and it's ATX http://www.dabs.com/products/asus-intel-performance-bundle--includes-p8z68-v-lx-motherboard--intel-core-i5-2500k---8gb-ddr3--7VJG.html?q=bundles%20motherboard&src=16
YOU WHAT!!!!!!!!!!!!!!!!!!! No way mate, you goto OC the chip, 4.0 easy with the intel heatsink but for £25 quid http://www.overclockers.co.uk/showproduct.php?prodid=HS-001-GD&groupid=701&catid=57&subcat=1395
Here is the link to the best OC guide which I use. You can get 4.6 with little effort. I get 15fps more by OC the chip.
Nice rig you will have peter ...yeah defo OC it to at least 4ghz..with a reasonable heatsink as heatsinks aren't much ...do buy decent paste like arctic silver as thermal efficiency is far better...and at 4ghz oc which would be easy you would see at least 10 fps more in games ...Let us know how you get on with your build etc peter ...