power cable for esoteric

I have a esoteric dv-50, vtl 5.5tl pre amp and a vtl st-85 amp, I have cheap wall mart type cords now.Should I use all the same make of power cables,or just for the dv-50& 5.5tl and a different cord for the amp.any suggestions?
I can only speak for the Esoteric -- you'll find others have their suggestions, but the older Shunyata King Cobra (Ver 1); which I had was UNBELIEVEABLE!!! Check out the Shunyata website and go for their best digital cord, that you can afford (or used) -- you will NOT regret it.

For your preamp -- again, a good cord is critical, but need not be at the level of the player.

I'm running stock cords on my McIntosh tube amps -- but, that's only because the MC-275A does just as well with the stock cord as it would with a mega cord (IMO).
I have a DV-50 and have gotten good results from both PS Audio Statement and Audience Au24 cords on the player. I have no doubt the Shunyata's work well too, I just haven't spent that much on a power cord, YET!
I have an older Esoteric transport, a P-10. I use an Acoustic Zen El Nino with it. This is AZ's entry-level cord but it very successfully does what premium power cords do. If I wanted to try a more expensive cord I might look higher in the AZ line to start with.
The top of the Mexcel which is distributed in Japan by Teac (Esoteric) is excellent with the X01-D2.
Yes, cables mentioned above are all good. 100 ft of Romex followed by 3 ft of exotica will enhance your listening pleasure. These products are truly unbelievable as one poster said!