Which speaker cable?

Would like some input for a new set of speaker cables. I am running a Rotel 1095 amp (5 ch) and would like to upgrade from my monster cables. I will be running the new cable to B&W's 805 Nautilus and B&W HTM2 center. The rear channels have been already wired into wall speakers and I wont replave them for another year. I've heard a set of 803's with Kimber, but not a before & after. Wanting a tighter bass and cleaner highs if possible through the wire. So, input please as to makes, models and costs.