In addition to their beauty, what's nice about daffodils is that squirrels tend to leave them alone. Daffodils are poisonous plants, and squirrels are no fools.
Another selling point for daffodils is their longevity. The growth of some bulb plants peters out over the years, and the plants die off. But through bulb division and seed production, your daffodils should spread as time goes by. Daffodils can be grown just about anywhere in the U.S., except for some areas in the extreme South.
Because they are early bloomers, daffodils can be grown under deciduous trees. While the latter are still bare, daffodils will be taking in nutrients from the sunshine via photosynthesis. Even after the deciduous trees come into leaf, daffodils will continue to store nutrients for next year, so resist the temptation to cut back the plants' foliage after the flowers have faded and died. As long as the foliage stays green, your daffodils are sending nutrients to the bulbs underneath them. These nutrients will be important for the next year's growth. But when the foliage begins to turn yellow, you can cut it off.
For more on daffodils, see white daffodils.