I used this forum extensively when setting up my system, so thought I would share my experience for others.
I have an early 2008 iMac (2.8 GHz) with a mini DVI to DVI adapter connected to a DVI cable connected to the Monoprice DVI & S/PDIF Digital Coax/Optical Toslink Audio to HDMI Converter. I also have a Toslink to Mini M/M from the 3.5mm audio out jack to the previously mentioned converter box. From that I have a 35ft HDMI cable running through the wall and attic to the living room next door connected to a Panasonic TH-50PZ800U.
When I first got this setup I was running Mac OS 10.5 and was not really pleased since it did not recognize the TV natively. Since upgrading to 10.6, it recognizes the Panasonic as a second screen at 1920 x 1080. I have experimented with VLC and Plex. Both work great, giving me picture and sound through this setup on the TV. The only issue at this point is the Apple Remote controls Plex or VLC and Front Row simultaneously (previously mentioned by others). This isn't too big a deal to me since my use is fairly casual.
It is great to have this working (with exception of Apple Remote) without having to use DisplayConfigX or SwitchResX. Thanks for everyone's input on AVS Forum that gave me the confidence to order these cables and converter box from Monoprice and get the ability to watch video from my computer on the TV.