SupraSteve-
There are too many variables to make any generalized recommendations with regards to a universal setting. Speakers, amps, speaker locations, it all contributes to good, or bad sound. It will take your ear and time to get it... That being said, I have found some commonality from system to system...
My background in audio includes a lot of experience, including running concert sound for a number of years as well as studio recording. I can tell you that your total stereo system will be happier and less likely to clip or distort if you start your tweaking by CUTTING frequencies to see if you feel it sounds better or worse. For the center frequencies of the Clarion EQ you show, I would focus on 315 and 2.2K
Lots of audio systems can sound muddy, and cutting at frequencies near your 315 Hz center can remove muddiness and improve power handling. It can also make the low bass appear tighter and louder.
Vocals from some performers can literally make my ears bleed on some audio systems. Lots of times I find that cutting at or near 3K will remove the "screech" without lowering the overall vocal level too much. Your 2.2K control might be able to affect a similar improvement. try turning it down and see what you think.
Be careful. It is easy to think that you have found a setting that you think really sounds way better, only to find that 30 minutes later you are adjusting things again. It is easy to over-do it, and the perception of better is often due to LOUDER, not better. It is also easy to get to a setting that just simply fatigues your ears; it hurts to listen too long. A well-tweaked system will be comfortable even at loud volumes, and will allow you to listen for hours with no fatigue. If you can get to the point where it just sounds smooth and effortless, and you can sit and listen for a long time without messing with it, you probably have found that point.
Or you will forever fiddle and fiddle and fiddle with it, just like the rest of us do...
me included.
Have fun with it!
Phil
Kicker