DVR apps
Windows XP Media Center Edition is the all-in-one solution for living room media moguls; it acts as a DVR, a media player, and more--all seamlessly integrated with the rest of the Windows OS. Media Center Edition is only available bundled with new machines (or add-in cards), but several easy-to-use alternatives on the market will work with existing system setups.
Hardware
TV tuners are great for time-shifting programming, archiving favorite shows to DVD, and avoiding wonky cable-box DVR apps and monthly subscription fees. For those without a spare PCI slot or unwilling to crack open their cases, external USB 2.0 tuners are the way to go.