This tool can help determine if legacy equipment will support Windows Vista.
I ran the tools on a laptop purchased this year, and the tool says I would need a TV tuner card to run the home premium version of Vista.
"TV Tuner card
Make sure you have an approved TV tuner card No compatible TV tuner was detected. Upgrade Advisor did not detect a TV tuner card in your current system. To watch TV on your computer, you need an approved USB-based TV tuner or TV tuner card. Contact your computer manufacturer for more information."