Video from computer to TV?

Does anyone know what the best way is to connect the video from my desktop computer to my TV? Some sort of wifi streaming?

I have seen that Apple TV can play videos from iTunes, but iTunes videos are limited in formats (e.g., no .AVIs) and it doesn’t like it would work for sites like Hulu. My goal is to cancel my cable subscription and connect TV from over the internet to my home TV set via some sort of computer interface.

I have a Panasonic Vizio HD TV with HDMI input but also conventional co-ax, S-video, and component inputs. There is no VGA input though.

Since my computer is in a different room, I probably don’t want to have to move it and directly connect it. I’d rather find a way to stream to the TV via some sort of box (Apple TV?, Roku?, GoogleTV?, ...)