Wire vs. Vibration vs. Power Cond. is best?

I don't think there is one 'correct' answer for this question. Is the starter system is something from Snircuit City or Best Poop, a mid-fi collection; what is 'nothing or the worst quality'? I think you need to define a baseline here.
I have taken a friend's cheap rack system and just added better speaker cable with thrilling results. The next step was to modify their systems positioning for better sound. Then isolation / damping, and last a speaker upgrade. At this point, the owner of the system concluded that a better receiver / amp-preamp was needed. Then it was the source units. Then interconnect came into play, and then a power conditioner.
A second friend had a Rotel / KLH based system. Here, interconnect, speaker cable & speaker stands, in that order, made the biggest initial improvements.
In my experience, better wire (generally speaker) will make the biggest difference, in a lower quality system. It has not been the case all the time, but frequently enough, this has been the 'push' that got these people more involved in their music, and prompted them to further upgrade their equipment.

Except for vibration isolation for a turntable, take all the money you might spend on that stuff and upgrade your speakers, electronics, or source for the biggest improvement.

Well I started with power cords, dedicated curcuits and power cords followed by vibration control. This may seem backwards to some but it was a budget issue. I can make more improvements for less money starting where I did.

I was meaning, not having any vibration control, and power conditioner, and cheap cables. I was just thinking in general with a typical hi-end system, were would money be best spent.
Maybe can't make generalizations but I was thinking maybe a power line conditioner before spending a similar $300-$1,000 in speaker cable /IC's.
Since speakers have a big influence on sound, maybe cones under the speakers would be most important if this would reduce speaker box resonances. I don't know, I'll be trying them all when I can.