Many customers ask for knives to perform certain tasks or make a task easier to accomplish. No matter what knife you choose it should always be kept sharp. A dull knife is more dangerous than a sharp knife because the sharp knife goes where you direct it to go.
There are many tools to sharpen knifes, from ceramic sharpening stones, to oil stones, to sharpening steels. There is a difference between a regular steel and a sharpening steel. A regular steel is designed to take the burrs off the blade once the sharpening is done; it will not really sharpen.
If you have prime rib to carve or a steamship round I suggest using a carving knife.This knife is unique as it is ribbed bladed making it easier to slice through tougher meats. The purpose of the ribs is the fat from the product you are cutting collects in them and allows the knife to cut smother and thinner.
If you want to cut tomatoes by hand you can use a serrated bread knife which I have used for lemons, limes and naturally bread. The serration allows you to cut through the crust of the bread and not damage the interior. The ability to go on forever regarding knives is never ending, however remember the use the right knife for the right job and keep them sharp!