Axiom Home Page Forums General Discussion Home Theater Digital Optical Vs. Digital Coaxial

Need this suggestion from a true audioholic. For better sound (including 5.1/6.1 or 7.1 channel surround sound), is it better to connect DVD player with a digital coaxial or digital optical? I want to connect my
1. Sony CD changer with my 7.1 channel A/V receiver.
2. My Blu Ray DVD player (with Dolby True HD and DTS HD) with my 7.1 channel A/V receiver.

Also, is there a benefit to using an equalizer between my CD player and A/V receiver or is it better to just play my CDs flat. One down side of using an equalizer is that it wont give me a digital output.