Speaker cables for Kef LS50....

I'm putting together a 2nd smaller computer-based music system in my den, and am looking for some input on a speaker cable for the Kef LS50's I'll be using in the rig. The run will probably be in the 20ft range, and I'd like to keep the used price budget to around $500 but I'm willing to push things a bit for the right cable if need be.

System is:

Kef LS50
VTL IT-85 integrated amp
Meitner MA-1 DAC
Wireworld Platinum interconnects
Acoustic Revive USB

Anyone out there who's stumbled across a cable with some synergy for their Kef's, I'd like to hear about your experiences.

I've been using Audioquest GBC, I like them alot. I bought
them at HCM Audio. They are discounted there. I had Clear Day
Silver Shotgun but I switched speakers & they were a little
short so I also had the GBCs around & they were the right
length. They seem to be a better match for the LS50s. The
give a fuller sound.

I'll add those to my short list.
Vinylvin, are you still using the GBC of with the LS50s? If you tried something else, what did you try and how did it work?

20 feet? Wow, I don't think you're going to find anything in your price range. Personally, I'd probably just get some 12-gauge Belden from Blue Jeans Cable and start with that. I'm not sure that anything for $500 for 20' will be any better. Maybe worse.
Yes, I am still using them. I can't really fault them, they sound great to me. I used the Clear Day Shotgun when I first bought the LS50s & they seemed bright, to be fair it could have been because the Kefs were new.
Thanks for the reply, you may want to try the silver wires again.