Best interconnects used for around $500 +?

I've recently replaced my FMS Nexus IC's with Von Gaylord 7000 ICs. If you can find a used pair of the FMS Nexus cables, you'll be more than happy. They were really expensive when new, but can be picked up within your price range used. 

If you are on a budget and know how to use a soldering iron then DIY is the way to go. Use AWG 16 gauge fine silver wire dead soft (Riogrande) and untreated cotton sleeve as dielectric. Go for best termination plugs pure silver (WBT or KLE). Kimber's top of the line Select interconnects don't even come close! 

Purist most musical.

Several Years ago when I had a CJ CV12 preamp I used MAC silver cables with good results. Currently I too use Clear Day ICs with my Odyssey system including a tubed preamp. Very nice combo. But I did test drive the Ohno and Purist Vestas. WhileI thought the Ohnos were thin sounding the Vestas were beautiful, musical. They run around $300. I had two sets testing between dac-pre and Pre-amp. Ultimately I went with the Clear Day for additional detail but if you are looking at musicality vs detail with less musicality the Purist were really something. I can only imagine as you go up the line. I tested both through the cable company. May went to test two pair of each to put get the full picture. Regards.