The materials that I use for knives often depend on what the knife will be used for.  I make some blades out of stainless (440C and ATS-34) and some out of tool steels or carbon steels(D2,01,1084, and 1095).  I make many different handles but love the exotic hardwoods the most.  A few of my favorites are spalted maple, cocobolo, walnut, and california buckeye.  I also do stag, elk or water buffalo horn.