I would tend to use a network solution because any other solution an you will have multiple copies of your music sitting around.
Another option is one of these. Its how I do it :)
You put one of those by your stereo and plug in into the back of your amp and bobs your uncle. You just stream the music to there. You control it from your computer, or a free app on your iphone or ipod touch.
You could pick up a second hand one of these for $100 I'd think.

