Best used speaker cable to match my system on Agon

I would stay with AQ S/C's unless you want to replace the I/C's also. Rockefeller or Gibratar will be a HUGE improvement at a very reasonable used price.

I am using a shotgun run of Gibraltar to my B&W 803D mains and I am very satisfied with them although I'd like the Mont Blanc but a shotgun run is a little too much $$ for me.

They use the same PSC+ but the Mont Blanc uses AQ's counter spiraling technology.

It really depends on the brighness or lack thereof of your speakers, imo. When I use to have a HTM3S center with B&W's aluminum tweeter the Gibraltar was too bright with that tweeter and their lesser prices CV-8 DBS sounded better. When I moved up to the HTM2D with the diamond tweeter the Gibraltar was the AQ cable of choice for me.

They can be had here on AG for attractive discounts.

Good cable for the money.

Any decent cable is going to be better than the Monster's imho.

Also, if you have the money, the Colorado's are a big step up in that they use Teflon. The Columbia's are the same as the King Cobra's except the Columbia's use the DBS pack.

If you are considering the Nordost try to demo the Nordost hiemdalls if they are in your budget. I have a nordost demo case right now and I find the blue haven to be a little on the bright side compared to the hiemdalls and freys. As you move up the nordost line the little more brightness goes away and more 'air' is between the vocals and instruments in my opinion. I personally think that the hiemdalls are pretty much at the point of diminishing returns (although I just bought the freys) for a tad more 'air'. You have to consider just how much you can afford for the sound you are looking for.

Also I think for the money the AQ line is the most reasonable for its price points but just not my cup of tea for long term listening (JUST MY OPINION and do have a pair of the King Cobras on my dvd player).