[quote=Aaron Ledger]
You are correct that the PC will decode the Dolby soundtrack. With the speakers you selected, the PC should be configured to downmix to stereo.
[/quote]
Understood.  I had considered some of those Logitech USB Z-Cinema speakers, but I read a number of posts on the Logitech forum.  Enough to scare me.  Thus looking at the Z-623.