Nothing really, you just need a TV and graphics card with a TV out option and you are all set as far as hardware is concerned. Oh yeah and a computer as well, but I assumed that it was common sense.
Yeah, that is because televisions are not designed to display very high resolutions and have high refresh rates, that is why its horrible to use an ordinary television as your monitor.
The problem with using TV-Out is that a standard def. TV runs at 720x480, interlaced. Your computer runs at whatever, non-interlaced. That conversion is what kills it.
Just look for a TV with VGA or DVI input. Any LCD or Plasma TV should carry this.