Homemade mayo has a far fresher flavor than its supermarket kin. A voluminous batch of the stuff can be had at the flip of a switch, by beating egg yolks, lemon juice, and oil in a mixer. Purists with strong wrists can always whisk by hand.
It's best to avoid raw eggs if you're serving babies, young children, pregnant women, the elderly, or anyone with a fragile immune system. Another option: Pasteurized eggs, which eliminate the risk, are available at some supermarkets.