interconnects vs speaker cables vs power cords - which make the biggest difference?

Perhaps/Maybe, depending on system components...
1) Power cords (NO conditioner and/or station)
2) Interconnects
3) Speaker cables
or
1) Power cords (NO conditioner and/or station )
2) Speaker cables
3) Interconnects

but they all make differences even when done individually and in varying order...

I agree all make differences.good cables design to make the system to perform at its best potential, bad cables tend to change/ manipulate the sound.synergy betweens cables is very important and have to be choose carefully. Not always the expensive cables are better than the cheaper ones , demo is a must!

Happened to come across what I believe to be the best power cord I've ever experienced...and it was free!  It beat my $4k plus PC's I have on hand.  Any guesses what it is??

@dave_b Sure, it's the stock cord that came with your Krell. 

Everyone, I heard an interesting presentation recently from Josh Clark -Lead Product Designer at Transparent Cable. An attendee asked "If I can't afford to add your cables to all my system at once, where is the first place in my system to invest?" The reply was the interconnect between source and preamp. I thought that was notable advice from an articulate and well informed source. Cheers,
Spencer

it is notable advice from a guy who sells cables

if a double blind test shows significant differences from interconnects then somebody really effed up the design of your components

if a double blind test shows significant improvements from speaker cables then you most likely have a speaker with unusual impedance match requirements ("not that there is anything wrong with that")

if you like your speaker cables then you can keep your speaker cables