A good chef's knife serves a lot of purposes very well and gets the most use in my house. But some knives are better for some tasks. I have a chefs knife that I use for the majority of chopping tasks for cooking prep. But I also have paring knifes for slicing small things, fruits, cheese, etc. or where finess is required that a chef knife is too unwieldy for the job, a bread knife for bread (duh), a boning knife (it doesn't get a ton of use but is nice to have when needed), and a very nice Santoku knife I only whip out when I need to butcher a chicken or something and need a bit if chef knife and a bit of cleaver. I also have serrated knives for cutting meats, and butter knives for butters and spreads.