wireless AV from latop to stereo

There are a number of such devices but I have no info on how well any of them work.

Are you focused on using the laptop as the browser/player, like a big, awkward, but feature-rich remote control? Rather than, say, a normal remote control or an itouch/iphone?

Are you intent on keeping all the media on the laptop instead of on a more dedicated server?

If you can loosen up your answers to the above, you will have a lot of great options like apple tv and other digital media players.

Other than iTunes + airport (which sounds like a perfect mp3 solution for you), I can't think of any way to do video other than the new intel thing or using a digital media player (one that you can control from your laptop via a web interface, not sure if this is common) hooked up to your TV which is pointed at a share on your laptop to find it's media files.

What about bluetooth? I have a pair of bluetooth bookshelf speakers in my office that I use wirelessly with my desktop.

I use netremote which is a remote program used on any windows device (WM, Win7, winCE) and set it up to play music from my HTPC in living room and Desktop in office. You can see the songs and videos that are located on that PC and tell that PC to play it. It's super simple to switch zones (PC's) and play another song on that PC.

Only problem for you is you'll need a PC connected to that stereo. You could easily pickup a cheap pc new for like $250 and i believe netremote is like $20. Promixis has a 30 day trial on their site. check it out.