I'm wondering if it would make a significantly improvement if I burn all the MP3 files onto CDR and play them with a CD Player that support MP3? Or do you think I better off relying on the soundcard's DAC to decode them?

For now I have the older SoundBlaster Live 5.1, so far I couldn't hear any interference or anything but I think it could sound better though. I don't know if I should get a new CD-Player with MP3 capability or just get the M-Audio Revolution 5.1/7.1 soundcard that everyone raves about, the M-Audio has a very good spec it's like S/N 107dB and THD 0.002%. My HK 3480 stereo receiver doesn't has any digital input and it doesn't has DAC either, so either way I'll still have to run the analog line to the receiver.