The Transparent Reference XL is the best for many systems, but it really is system dependent. If you have Levinson, Pass Labs, Krell, Classe, Rowland, Audio Research, Nagra, the ref XL is fantastic. Especially with any of the Wilson, Revel, Sonus Faber, B&W, and Maggie speakers.
Ultra transparent with great bass?
I am interested in a speaker cable that is ultra transparent with great solid bass. I havent't tried them all, but I have yet to hear one that is both. Budget is under 5k.