Belkin Easy Transfer Cable for Windows Vista
Does exactly what it says on the box
On you old PC, load up Windows Easy Transfer, tell it you want to use a cable to transfer your files and then plug the cable into both PCs - wait a couple of seconds and the connection should be recognised.
All that now remains is telling the program what you want to transfer and then sitting back while it dutifully copies over all your files and settings. The default option is all user accounts, files and settings, which will pretty much get you up and running on your new PC as you were on your old one.