I too can confirm that it is possible to hook up a MacBook to an HDTV (in this case a Pioneer Elite). I needed two cables: a mini-DVI to HDMI cable (see "
PTC Mini-DVI to HDMI Adapter with 6ft HDMI Cable for Macintosh") to carry the video directly to the TV, and a 3.5mm to component (red & white jacks) "Y" cable (see "
Belkin Audio Y Cable Splitter 1-Mini Plug/2-RCA Plugs (6ft)") to carry the audio directly to the TV. Note that I bypassed the A/V Receiver and went straight into the back of the TV.
In order to make this work, I had to change the settings within the setup menu of the TV itself to get the audio from an analog source (while retaining the video from the HDMI cable). Normally the HDMI cable would carry both video and audio, but there is no audio coming out of the HDMI port on the MacBook so you need a second cable coming from the MacBook's headphone jack. With decent speakers hooked up directly to the TV, this produced very acceptable stereo sound. The picture was quite good as well (maybe not HD but I was able to watch Hulu video as well as DVD movies on the 50" screen with no visible granulation).
This setup sort of obviates the need for the $100 Roku box I have (which allows you to display HD instant-download movies though Netflix). I can now simply play them on my MacBook though this new setup. The audio cable was $5 via a 3rd party vendor on Amazon (shipping included) while the video cable was $12. So using your MacBook for Netflix instant downloads is $83 cheaper than Roku.
Hope this helps. I'm very happy with all the options I now have for fully utilizing my 50" HDTV.

Oh, and, I read the ****ing manual (RTFM) to figure this all out. You should too.