New coputer with Windows 7 PRO 64 moving data from old computer.

I just finished a new computer for my wife for her work. The old computer has a Windows 7 PRO 64 upgrade installation from XP on it. I bought an OEM version of the same W 7 PRO 64 with SP1 to install on the new computer. I need to know the easiest way to move her files from the old computer to the new one, but I would like a clean install of the operating system if possible. The new computer has 2 SATA 3 drives, the old one is using the older SATA drives. Can I just move a drive over with all here files on it and have the new system find it? Or do I need to hook the 2 together and pick and choose the files she needs to transfer?
Thanks in advance for the help.
Lyle

The upgrade license can migrate to the new build providing there is a retail copy of XP or Vista to qualify for its use - neither need to be installed first, just leave the key blank during install and afterwards do the quick registry workaround in Option 3 of Clean Install with a Upgrade Windows 7 Version.

Otherwise the easiest way to make sure everything gets transferred is laid out in the same steps for Clean Reinstall - Factory OEM Windows 7. If you'll stick with the tools and methods given you'll get and keep a perfect install.