Many spring-flowering bulbs, including tulips and daffodils, make excellent cut flowers. Stems should be cut as soon as the buds show color. The flowers will open in a day or two and remain in good condition for about a week, sometimes more.
Before combining tulips and daffodils in the same arrangement, keep them in separate vases for 24 hours. The sap from freshly cut daffodils can reduce the vase life of tulips.
Note: If you cut flowers from a bulb that you want to grow and bloom again next year, cut only the flower stem (in the case of tulips, it's fine to take one leaf so you can get a stem of reasonable length). The leaves need to stay attached to the bulb so that it can store up the energy needed to make the next spring's blooms.