Power Cables


I am currently upgrading my system.  I had a pair of XLO Ultra speaker cables sitting around and was very impressed with the improvement over the original Monster cable.  Having come back from Axpona, I am wondering what fellow Audiogon members would recommend for a power cable with tight bass, superb mids and extended highs that would help to produce a very full, wide and deep soundstage.  I am looking to replace the cable on my Adcom GFA-5802.  I do agree with philosophy of starting with the power.  I have demoed one other power cable and the difference is immense.  Thanks in advance for the advice.
spipa
As a owner of mc452, I dont think a powercord will do so much to an amp.  I have no idea why people could hear so many different things from copper /silver what the cable is made of.   I can sell you my nrg2 if its not too cheap to you. I bought it because it looks better than the standard cord. 
For amps, I have used all iterations and generations of PS Audio cables. Currently running AC-12 and love it. (I'm using all Shunyata for my front end). 

I don't know much about electrical engineering, but keeping it simple with high quality copper of a decent gage has served me well on amps. 
If I may suggest a power cord that has literally transformed my system to greatest levels. Clean, dead silent, alive, life-like. I cannot stress if anyone should try these power cords will not be able to take them out....they are that good........anyone??
Core Power Technologies. These are seriously amazing power cords. I think once you try these in your system your jaw will drop in amazement. You WILL keep them in your system. They have a 50, 150, 300 model.