Hi there
Ive had good results (so far) with buying a Tacima 6 way conditioner, putting a ferrite magnet on my amp mains (its a fixed lead so difficult to upgrade to shielded) & making my own mains cable for my PS3.
The soundstage has improved alot - no placebo'd effects at all, it did make a difference.
As for my own mains, the ps3 - i will be honest i have not noticed much difference, perhaps a little smoother & more defined in colour but can not gurantee that. But again the sound quality is better, so im thinking the Tacima has done most of the work, but making my own lead will not have made it worse. Plus with all my wires & wireless & ethernet leads etc & mains wire, it will definately be helping against the interferance.
I am going to make my own lead for the Panny plasma & sky HD when that turns up. As the price thats charged for mains is OTT for myself, so i made my own as i like a bit of DIY 
I also shortened the Tacima from 2m to 1m & used a MK silver plated toughplug & 13 amp SEM silver plated fuse.
My own PS3 lead consisted of MK tough plug & Fig 8 (C7) plugs both silver plated, a SEM silver plated 5 amp fuse, high content silver weld for the fig 8 connections & Supra LoRad mains shielded, twisted cable 1.5mm silver wire. Very high shielding, can deffo recommend this cable. It can run 10amps, which is way more than req'd. & overall its far cheaper making it myself. I also have nice braided black sleeving that expands & fits around the cables & some heat shrink to give it the 'professional' finish! 
Edit to say, i did have a tight fit with the 1.5mm cable into the fig 8 plug, for you to bare in mind, i had to cut the sleeving back to the start of the plug & run just the 2 wires in for the connections, but with careful cutting, heat shrinking & patience it turned out well.
So to finish off i will get 2 more MK silver coated plugs, another fig 8 silver coated plug & i have an IEC plug silver plated already. I will also be buying 3 mtrs of the supra lorad 1.5 for the tv & skyhd.
Panny TX-P42G10, Monitor Audio BR2's, Monitor Audio R45/R360 package to make 7.1 (all Walnut finish), Soundstyle Z1's for BR2's, Yamaha DSP-863SE AV, PS3 Slim, Wii Black Ed., Xbox 360, Tiscali TV, Harmony Remote. SKY HD due 30th Nov & counting!