What's the best way to play media from my hard drive on my TV?

Leo says that the GoFlex is a good one. It's a USB Portable hard drive that has Wi-Fi built into it, so he can stream to a laptop.

Connecting to a TV, A machine with Plex would be a good choice.

The Western Digital WDTV would play any format as well. It's essentially a media player with big drives and is very affordable.