In my opinion, the place to begin is with one or better yet two dedicated circuits with 20 amp breakers and wire runs of 10 gauge although 12 gauge would work. In addition to that use high-quality AC outlets.
Agree completely and that's exactly what I did when I set up my current main system (I located the system in the next room to the main panel).
I use a filter (Inouye - http://inouye.ca/index.php?page=Products) on all front end source equipment (sources, phono preamp, preamp), which makes an obvious improvement, but not on the power amps, which suck too much to go through most power conditioners.