I have only very recently started looking into mains cable upgrades. I firmly believe better speaker cables and interconnects give you better sound and vision so it follows better mains cables should do the same.
It also makes sense to me that products should be matched.
I wouldn't buy a £10 cable if i had a £5000 amp. Neither would I buy a £500 cable if I had a £400 amp.
Russ Andrews have a mains cable for sale for £3350!
So...what kind of system would I need to benefit from a mains cable costing over £3k (My Pioneer KRP-600A didn't cost much more than that!)?
http://www.russandrews.com/product.asp?lookup=1®ion=UK¤cy=GBP&pf_id=1549&customer_id=PAA1843081809326PSQGZOIRGKCTDSXO
Pioneer KRP-600A, Pioneer LX08, Pioneer SC-LX81, Sky HD+, Tannoy Revolution Signature DC6T, DC6LCR, Arena Highline 500 Rears, Sunfire HRS-12 Sub, Chord Silver Plus HDMI & Chord Rumour Speaker Cables, Clearer Audio Mains Cables, AV Podium Rack