Effective AC power conditioners for digital??

I have tried several devices and they all worked equally well. Perhaps my noise problem was minor. I think it is worth trying several devices and comparing. In theory once you eliminate the noise problem (does not change with conditioner) and your equipment is functioning properly once again then it probably does not matter what "brand" conditioner you use - after all the noise doesn't know or care. FWIW I found only one component to be suffering from a problem (the other devices didn't care about conditioning or not) but I may be just lucky and already have cleanish power.

I too have always found purchasing higher quality components with properly designed power supplies avoids the detrimental effects of conditioning altogether.

Absolutely agree. I would add that switched mode power supplies - which have become popular over the past fifteen years are a big part of the problem. These are inherently noisy and add noise back into AC wiring. TV's, Cable Boxes and PC's all often use switched mode power supplies - they are cheap...