For an Adcom 5802 I wouldn't go crazy. Kimber PK10 Ascent will be plenty good or find a used but same PK10 Gold. $400 or less new. If you don't have dedicated circuits and decent receptacles to start with you're not going to hear the full potential of your amp or a better PC. If you don't have dedicated circuits, I'd start there first.
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.