, the kind of steel the blade is made from can be a determining factor. You can choose between the standard high carbon steels to Stainless Steel or several of the newer exotic ones. Of course the steel is not the whole picture, you need to consider the construction of the knife and if the steel correctly heat treated.
Of course many people prefer the high carbon steels because they are easier to keep sharp and stainless steel may keep its edge longer but can be harder to sharpen. Also consider what you might be putting your knife through and the environment you live in. Being high carbon steel is less corrosion resistant you may get one with a coating on it to help preserve the steel.
If you use it for fishing or live in very humid locations a stainless steel blade may be preferable. You would not have to do so much maintenance with stainless, just wash it off and dry it. A common carbon steel would be 1095 which is considered a tool steel which is tough enough, holds an edge well and is not too expensive.
A good compromise between high carbon steel and stainless would be D2. It is a high carbon steel with a little higher percent of chrome. This gives it more corrosion resistance and toughness that many may prefer with out going to stainless. You see many different grades of stainless steel for blades and each has its own stain resistance and toughness.