I know Gary..:(
Planning to build a new system in couple of months (buying piece by piece) and i will go with 10s...unfortunately. I won't go near 11...
Check out pcpartspicker, good for compatibility, and pricing. If by chance you are not going to replace the MB, you can still upgrade 7 to 10 for free, even if the 7 was an OEM copy. I just recently did that to an old computer of my wife's that had a virus on the hard drive I could not get rid of without a format. Her restore disks would not work on the unformatted drive, and I wanted to change the computer over to a SSD anyway. Her computer had never been updated to SP1 and could not find a viable source of SP1, so only choice was to take it to 10.