I recently faced an audio/video problem with my MacBook. I subscribed to the great MLB.TV service so that I could watch my Cubs games out here in Los Angeles. However, instead of just watching them on my MacBook, I wanted to actually watch them on my HDTV. My first solution was to go get a Mini DisplayPort to HDMI adapter, but there was an issue; I would have had to figure out some way to hook up the audio since MacBooks, before yesterday's update, only output video over the DisplayPort. Audio would have needed to come through the headphones or the USB port separately.
Fortunately, that problem is now fixed for new buyers; the most recent MacBooks, according to this support document from Apple, will send both audio and video out through HDMI as long as you've got a VESA compliant adapter (which most DisplayPort adapters are). Of course, I'd need to buy a new MacBook (which is much more expensive than just figuring out an audio solution), but at least the issue is fixed on the latest hardware.
My eventual solution? I was saved by Sony, of all companies. MLB released a free app on the PlayStation 3 (which I have hooked up to my TV via HDMI as well) that lets me watch my subscription without the computer. That leaves my MacBook open for other tasks, like blogging, while I watch the game. Let's go Cubs!