Anybody could advise cables for my system.........

I used to use vintage audio gears in the past so I have least concept about brands and types of speaker cables and interconnects. Recently for experiencing different taste of sound I change my system and I'm now in need of information about interconnects and speaker cables to select.My system:

Transport Audio Research CDT1
DAC Audio Research DAC3
(Between CDT1 and DAC3 I use Audioquest AT&T
digital cable)
Pre-amp Audio Research ReferenceII Mk II
Power-amp Krell KSA250
Speakers Duntech Sovereign 2001(Single-wired
version)

In urgent need of advise from any of you about interconnects(about 2m,Balanced-terminaled) and speaker cables(about 12 feet,either Y or banana-terminaled will be fine).
Thank you!
Rick