A few random points to add to the discussion -
Paragon programs are mostly junk...rebranded junk they have bought from other companies and put their new skin on. There's nothing they sell that you can't get the equivalent elsewhere for the same price or cheaper.
Curt, to get past your current nightmare, borrow someone's Vista disc and do an upgrade over the top of the old OS. It won't be pretty & Vista probably won't activate, but you'll have time to copy off the files you want.
OEM versions of Windows - You will be fine with an OEM copy. I have friends that have upgraded their PCs (including their motherboards) and Windows activated again just fine. There's especially nothing to worry about if your current install is 6+ months later than your last install with that disc. MS keeps activation data on their servers for only six months.
Upgrade versions of Windows - Depending on your levels of patience you may want to avoid one of these. An upgrade version will only activate if it's been used to upgrade a 'previous' version of Windows. If someone has a bare hard drive, that means that in order to get around this annoyance, they'd have to install their upgrade disc, not activate it, then reinstall Windows again as an upgrade to that 'previous' version in order to activate it. IMHO, life's too short to install Windows TWICE every time you reinstall your OS. They *may* have fixed this for Windows 7, but with Windows Vista it was the only way to use an upgrade disc on a bare hard drive.
Final point - Ultimately, with Windows 7 it doesn't really matter what kind of disc you have any longer (retail, upgrade, OEM, etc) as the serial dictates what type of Windows you have not the disc, as it was with previous versions of Windows.
Get yourself the OEM version of Windows x64 and enjoy life (and your savings). Once it's installed & activated your or nobody else will be able to tell a difference between it and the $400 copy you saw for sale.