Here are some of my favorite Trader Joe's items:
Staples: milk, yogurt, eggs, bread, coffee (the best), grains, pasta
Produce: I now primarily use the farmer's markets for fruits and vegetables, and purchase citrus bananas, and some Prepared vegetables and fruit (best price on blueberries anywhere)
Snacks (for kids and adults): Fruit Leather, Trader Joe's Cheese puffs, LARA Bars, Dried Fruit, Nuts, corn chips, cheese
Frozen: Vegetables, shrimp
Other: flowers, hand soap