Yup I am gonna get F4's think I have decided on using windows 2008 R2, I still would like confirmation that I will be able to connect the Optical header to the hard drive that comes with, I can then mount that in the top bay and keep the 4bay for the F4's and Raid 5 through windows.
Yes you can use the Optical drive header to run a 5th harddrive or even the esata for a 6th drive. The instrauctions say you should use a sata cable with a right angle at one end as the sata connector on the board is right below the drive caddies and there is limited room to fit a straight cable but it has been done. You'll also need to install a custom bios to get the esata and the optical drive header running at full speed, details here