Anything you can do to condition power externally can be done internal to the audio equipment (stereo, keyboard, etc). So what you get out of doing this will vary depending on how susceptible the equipment is, by design, to your particular input power behavior. Also, conditioning could already be handled anywhere along the power line from your house back to the power station and everything between. Certain geos power is historically noisy - some it is historically "pristine".

I've got a surge protector. These have some form of conditioning. But my goal is in protecting (to the degree that I can) from catastrophic failure vs. trying to get any different sound out of the instrument.

Most defiantly yes...In the UK i am using a large Advanced Balanced Mains Power Suply unit by Air Link transformers with the edition of other passive filters at the pre balanced mains stage and doing A/B comparisons you can not miss the difference in my home studio this also includes a dedicated studio ring main but this is a much bigger subject than the original Question to get into and you can spend small or large sums of money approaching this subject so as a start look for mains condtioners with a broad spectrum of filtering specification.