Spkr, interconects, or power cable upgrade first?

Replace your power cables first, you may not need to replace anything else.

Seems like mixed opinions so far. I can only cite my experience which was: replaced speaker cables first, then interconnects and finally power cables. I too was using Monster cables for speakers. They'd developed quite a bit of oxidation over many years. Went with JPS Labs for all cables (speakers and inteconnects). Some purchased used. Built a DIY power cord for my CD player (go on-line to Parts Express for instructions). Bought a MyAudioCable (MAC) powercord for my integrated amp. Along the pricing continuum for this stuff all the above are definitely to the lower cost end but good value options - at least in my opinion. For me changing out the speaker cables made the biggest improvement.

power cords first..
Larry

As I agree with Ghosthouse that upgrading speaker cables first is the way to go, you have an even three-way split so far. And like Metrella I also prefer solid core speaker cables; they are the only type of cables that I hear a distinct improvement with.
Concerning PCs, they are last on my list. All of my equipment is plugged in via upgraded PCs from various makers and if they make a difference it is subtle (please don't take my Audiophile club membership card away).

I ditto powercords, they make the biggest difference, if they are quality powercords!!
I suspect IMHO that folks that say powercords don't make a difference or at best a subtle difference, are not using the best powercords they can get for the money.
I say this because I was the same way until I heard what powercords like shunyata, fusion, purist etc.. can do.
It is also important to note where you put the powercord first. Again, IMHO you get best bang for your buck, if you start with the preamp then CD player and finally amp.