Davids response to my eq question sparked another question. Curious as to what ever one uses.

Plus some of the audio guru's might be able to jump in and rank them from highest to lowest quality.

Ipod/MP3 through headphone jack?
Ipod through data connect cord?
Ipod/MP3 through USB connection?
Audio CD's?
MP3 CD's?
Music added to IPOD/MP3 from actual CD's?
Music added to IPOD/MP3 from free downloads?
Music added to IPOD/MP3 from purchased sites such as amazon or itunes?

I have never used cd's in the boat. I either play through data port on an ipod or headphone jack of a droid. I did notice i need much more volume from the droid. Most of music, as of lately anyways, is purchased from amazon.

Never gave it too much consideration but after this stereo install i may consider a different route if there are quality differences.