The absolute "best" filter/conditioner for digital

Zd542's advice is spot on, but The cable company doesn't carry everything out there. Because of the unique interaction of your electricity with your system, no one can tell you what the best will be, and you could easily blow your whole 401K balance running the experiment. Sadly, finding the best is like winning the lottery, but finding something that works really well is not so hard. In addition to the Cable Company, talk to Chris at VH audio. The guy is a real straight shooter.

I came late to the power treatment party and have been astonished at what it offers.

Dedicated line(s) 1st.

I agree with Zd542 about trying things out, but in lieu of other information, such as your budget and what you're trying to accomplish, I always recommend the "first do no harm" approach of Shunyata. They have something for just about every budget and their gear has maintained incredible re-sale value over the years...which should tell you something.

If you want something inexpensive Emotiva has a nice RFI filter with 6 outlets for about $120. Works very good in my system. They also have a two outlet for $99 for power amps. It does not seem to harm dynamics at all and it also besides filtering correct for DC offset in the power line
Alan

PI Audio Uber BUSS.