nVidia will have Windows 7 drivers already built in and the chances are that the HP drivers will be as well, you could probably install RC1 (7100) and have no problems at all. Windows 7 is very good at finding missing drivers, it's problem solver even links to the URL so you can get the correct one if it's missing from Windows Update. I've plugged in several random printers and it's always been able to get the drivers from Windows Update.
The only driver I was missing was for Microsoft's LifeCam VX-3000 of all things, they did release an updated driver within a week or so though.