A coticule or escher are my choices. A pasted strop (Tony Miller makes good ones) is another popular alternative, and much easier to come by than either of the stones. A good pasted strop is also pretty easy to make yourself. Modern coticules apparently have some severe quality control problems, and Eschers are damn near unobtainable by anyone with budgetary constraints. You can get a good shaving edge with just the 8k, though. A lot of folks make that their final honing step.