I'm going to suggest something free. Go to the Cardas website. They have a speaker/room placement calculator which I found to be pretty effective. What was most unexpected is that the bass locked into the room better when I placed the speakers per cardas, which in my case meant pulling them a foot more into the room and away from the back wall. I also wound up bringing my speakers a bit closer together too.
As far as power options are concerned the single biggest impact I ever experienced was when I installed a dedicated 20 amp line to my system. It's a home run straight back to the breaker box, using 10 guage wire. Doing that cost less than a fancy power cord, and was more of an improvement than any power cord I've ever tried. For power distribution I use a simple wiremold power bar that Naim used to recommend, with the amp plugged direct to the wall. I think running the circuit cost about $150!
I'm all for free or low cost real improvements.