I just read an article in Widescreen Review that said some BD players won't play standard CDs. Here's a quote from Widescreen review:

"Note that the new Blu-ray Disc players
from Sony and Pioneer Elite do not play CDs,
while the HD DVD players do."

So you would also need another CD/DVD player if you want to listen to CDs. HD-DVD does play CDs IAW the Widescreen Review article.

Food for thought.