If you have a Mac that was introduced from mid-2010 on and it has a Mini DisplayPort, Kanex has a couple of solutions that can turn your HDTV or other HDMI-equipped video device into a monitor with full audio pass-through.
I recently had a chance to test out two such solutions from Kanex. The first is the US$29.95 Kanex iAdapt V2, which is an adapter that plugs into the Mini DisplayPort and has an HDMI port on the other end. It's useful if you already have an HDMI cable and just want to be able to plug it into your compatible Mac. The second is the $44.95 Kanex Mini DisplayPort to HDMI cable, which combines the adapter with a 10-foot long HDMI cable. You plug one end into your Mac, the other into your HDTV.
For compatible devices, which include the MacBook (Late 2010 release), MacBook Pro 13 /15 /17 inch (Mid 2010 release), iMac 21.5/27 inch (Early 2010 release), MacBook Air 11 /13 inch (Mid 2010 release) and Mac mini and Mac Pro (Mid 2010 release), you not only get a selection of HD video formats (720p / 1080i / 1080p), but also 5.1 surround sound pass-through. This could be extremely useful for business travelers who want to look at presentations or videos on a screen that's bigger than the one on the 11.6" MacBook Air -- they can turn to the large flat-panel HDTVs that are now in many hotel rooms.