I asked a question about speakers a couple months ago and created the following thread:
http://forum.calgarypuck.com/showthread.php?t=78587
I have been extremely happy with the quality of these speakers so far. For their size, they can pump out some very powerful, crisp, high quality sound.
I'm not an audiophile by any means, and I don't know too much about the technical specs of the system, but they have more than exceeded my expectations. They support both optical audio and coax.
Edit: because I didn't want to bump that old thread, I just wanted to note that I ended up getting them from Memory Express. I was able to get them to price match TigerDirect.ca, and got them for about $160 less than Memort Express' advertised price (I think I paid $340 for them). The manager was complaining about how they're selling them for under cost as he punched in the discount.
Memory Express has a price match policy where they will match any online Canadian retailer as long as you pick up in-store.