Does Airtunes streaming have to be wireless to Airport Express?
Basically I'm shopping for a better audio connection between my G4 desktop & my stereo. I'm considering the Edirol UA1X which is a USB to Analog (RCA In/out + headphones) & SPIDF converter for $80.
http://www.samedaymusic.com/product--EDIUA1X
Then I got thinking, I have no need for audio inputs to my mac. Airport express would give me high quality audio out plus a wireless network for $50 more (I have a laptop with an airport card). But since my desktop G4 has all my music & no airport card; can I stream using Airtunes over the ethernet connection thru a router?
Does anyone have good or bad experience with either of these products or a different product recommendations to solve my problem?

