I've had very good luck with all levels of Audioquest up to the King Cobra ICs and Type 4 speaker cable. After that it's gets either too expensive for me or a diminishing return IMO. Their power cords are great too- have them in almost every component.

Can I suggest Kimber 4TC as they are really very good value for money.

A caveat about Kimber- on a system that is already leaning towards bright, they can really push that edge. I also feel they are alittle bass shy, in general.