What connections are better?

Of course, multiple HDMI connections would be great, but....

My set has one HDMI input , 2 component inputs, 2 composite inputs(with
s-video) and one digital audio input(fiber optic), 1 coaxial input

What would give me the maximum quality?
I have my DVD player and Digital Cable Box.

Currently I am not using the HDMI connection.

I have the Digital Cable Box connected via 1 of the component input and RCA
audio jacks into my Home Theater.

I have the DVD player connected via component input and a digital Audio
cable.

Is the sound better or worse with HDMI as opposed to the digital audio
cable?

What would be my best scheme for connections?
If I have to choose either Cable or DVD for better audio and video quality
I think I would want my DVD player to have the best connection for watching
movies and concert DVDs.