There are two options here. The first type is high carbon steel. It is tough, and it will maintain the hardness and sharpness as long as you need it. On the other hand, it is expensive, and sharpening is complicated.
The second type is carbon stainless steel. It is a softer metal than high carbon steel, and it requires less maintenance. However, it is entirely immune to corrosion, and sharpening is simpler. This metal is better for most of you, due to the fact you can make the blade sharp again within seconds.