Originally Posted by Toss3
That's what the receiver would be for.
I'd say put together the cheapest possible htpc that can playback a high definition movie and get yourself a decent receiver and a good 2.1 sound setup for now(I'd recommend the z5500s, but as your wife has a big music collection I can't as they are pretty much only good for movies and games(compared to a decent 2.1 setup)). You can always add speakers later for the full 7.1 enjoyment(although the 780G only supports stereo PCM so no bitstreamed hd audio
I've already got a decent Sony DreamTheater system setup in 2.1 mode right now. To watch movies, I have to connect my laptop to the Westy and then RCA to the Sony receiver for audio. The sound is actually really good in stereo so I'm not really worried about 5.1 right this minute.
I've thought about buying a new receiver and using the same speakers but I may have to wait on that a little bit.