When building gift baskets, one of the most important things to consider is the recipients. If you know them, tailor it to their tastes. If you don't know them well, or are making the basket for a group, food and drink is often a safe bet.
If you know what the person likes, you could try a "design it yourself" gift basket. Most people appreciate the thoughtfulness of a personal touch in a gift. Including some of the person's favorite things is likely to go over well. It's also good to know if the person has any allergies or sensitivities that you should avoid. You don't want to give someone a gift they are allergic to, so avoid common allergens, such as peanut products or lactose products.
If you do not know the person well, or are making a large batch of baskets for a group of people, the rule is safe mass appeal. Candies and chocolates can seem like a good choice, but be sure you aren't giving them to a diabetic. Fruit baskets can be a healthy option, with both fresh and dried fruits. Specialty coffees and teas are very popular as well, and can accompany gift cards to a favorite coffee shop.