Hacked Apple TV’s can offer a few advantages over a non-hacked ATV.  With certain plugins installed you’re able to watch DVD Video_TS files directly on the unit, sort of like a DVD jukebox, but no DVD’s necessary. You can install OS X on the unit and use it as a computer.  There are even web browsers available as plugins too. The biggest advantage yet might be that you can install extra video and audio codecs onto the ATV and avoid having to convert every video file you download.