>>605542Whetstone, diamond, ceramic are all good. I enjoy freehand sharpening. I would avoid the v-shaped "pull through" sharpeners, mainly because the average person doesn't use them correctly. If that's not really something you want to get into check out lansky and spyderco sharpening systems. I have never used them but I hear a ton of positive feedback about both company's sharpening systems and there are plenty of reviews of their popular stuff on youtube.
Whatever you decide consider stropping your blades. I only recently started stropping my blades and the results have been pretty great for me. I didn't bother buying a genuine stropping rig. I just use the underside of my belt and am very pleased with the results.