While they're about $120/set here (Canadian funds, and overpriced store, mind you,) the Logitech X-530s might be a decent choice if you need surround sound. I personally don't care for them much, but they go louder than I'd ever need them to, have more than enough bass for bassheads (adjustable for those of us who are not) and have overall fairly clean sound. At low volumes, however, I find them extremely directional* (and while this could be the room I'm using them in, I doubt it.) The rear speakers are also fairly quiet. They're not exactly bad, they're just not great. For the average consumer, though, they'd be awesome. Hope that helps.
*: Granted, I don't have them set up in proper 5.1 (I don't have the room,) so that could attribute to an extremely off-sound. I know that having all the speakers on your desk (save for center channel on top) is the wrong way to go about setting stuff up, but I have no other option. Setting them up properly would make them sound better.
(And on another note: I'm hoping to ditch these at some point and go for some stereo speakers.)