A roommate of mine in college used to build speakers of much higher quality than those you could buy — and for less cash, too. The trick is knowing how to calculate the box size(s) properly. Add to that a little bit of crossover savvy and some basic woodworking skills, and you’ve got $2,000 speakers for more like $250.
Just plug “speaker building” into Google, and you’ll find zillions of resources to get you started. Radio Shack still sells a book with the required calculations, but now you can find all that material online just as easily.
And don’t forget to stop by my favorite online parts provider, Parts Express. I’ve bought tons of parts from them with good results. Of course, if you have a better source to recommend, by all means post it in comments. I can always use another entry in my little black book!
(Thanks, Dieter Karner, for the great cc-licensed photo.)