Usually you should just pick the latest Windows 7 driver from the manufacturer's website. Make sure that you choose 32-bit or 64-bit depending on which version of Windows you have. If you have Windows Update switched on, Windows may be able to download suitable drivers directly and automatically.
If no Windows 7 drivers are available, most Windows Vista drivers will be, since the driver models for most hardware types did not change. Some kinds of hardware will run with Windows XP drivers, but the chances of success reduce greatly at that point.
