Getting lumps out of yogurt, whisking together oils and vinegars for vinaigrettes, whipping cream.

Mostly for decoration. They look so pretty in the copper canister on the countertop next to the stove.

Seriously. . .I never use the biggest one because it's too unwieldy--that whisk really is just for decoration. I use the medium one for gravies, roux, cream soups and puddings. The little one is for popover batter, pancakes, scrambled eggs.

I wish I had enough patience to whip cream and meringue with a whisk. It seems so cool and professional.

Home defense.

I use mine for making beating egg whites for cakes and whole eggs for omelets, for mixing dry ingredients when baking and for quickly folding things into batters, whipping cream, and breaking up lumps in cream of mushroom soup and cream of wheat, and also looking mildly threatening in the kitchen. When I'm feeling strong I make mayonnaise.

Incorporating dry ingredients into liquids, or when I make sauces and gravies

Stirring my flour before measuring instead of sifting.

Stirring together vinaigrettes to make them nicely emulsified!

Stirring together dry ingredients when baking. Blending (and fixing) sauces.

so many things! whipping cream, whipping eggs if you want to give them some height, whipping egg whites for meringue, making sauces like hollandaise or sabayon.