I don't know what you're using just now, but assuming it is copper based, don't bother swapping it out for another copper one (it'll make as near as dammit no difference). Go for a silver based interconnect and use something like Nordost Blue Heaven. I found it unlistenable, but its going to be brighter and that's about the only time you'll see me recommending one cable over another...!
Something to do with the silver content makes it sound a little brighter than the copper equivalent apparently; no idea why!