which speaker cables to buy?

It is my experience that spending more than $100 - $300 is better for the ego than it is for sound reproduction. However, You will never convince anyone who has spent a lot of money on cables (wonder why?).

I'm a bottom feeder. I got a $1500 pair of PS Audio Xstream Reference Bi-wire for $350 on closeout. They definitely sound like $1500 cables, not $300 ones.

For the OP, I recommend these. If your speakers can be bi-wired, get these.

They're not a lot of money but should give you more than a taste of what carefully designed cables with quality materials bring to your system.

Seriously, you'd be hard-pressed to get better-engineered cable with better copper than the AudioQuest closeouts at HCM Audio. I provided the links in my previous post. We're talking $79.95 for an 8-foot pair of multi-gauge (12 ga. aggregate) solid core high purity long grain crystal copper with hand terminations of copper or silver spades or bananas.