Daffodils come in a wide variety of shapes, sizes, and colors. Here's a roundup of examples from each branch of the family tree.
Daffodils are hardy in Zones 3-7 or 4-9, depending on cultivar or species. If you live in the South (Zone 8 or warmer), precool your bulbs before planting by placing them in the vegetable drawer of your fridge for 6 to 8 weeks prior to planting; don't store with apples, which emit ethylene gas that prevents bulbs from blooming.
Prepare the soil by tilling 6 to 12 inches deep; amend with compost and sand for drainage. Daffodils can handle shade from deciduous trees, but not permanent shade cast by evergreens. Plant bulbs pointy sides up, 6 inches deep and 6 inches apart; for a 100-square-foot bed, you'll need 400 bulbs. In the North, try to plant your bulbs 6 to 10 inches deep -- they'll be less likely to be disturbed by frost heaves or the cultivation of later-blooming flowers.
Avoid planting too few daffs; they look best planted en masse. At about $1 a bulb in the stores, however, they aren't cheap; for large purchases, a better source is mail-order catalogs. One such is Van Engelen, Inc. (860-567-8734; www.vanengelen.com), which sells bulbs in bulk, making the per-bulb price affordable. Buy bulbs that are top-size (DNI) or at least DNII; you may wait years for smaller bulbs (DNIII) to bloom.
A classic trumpet cultivar, 'Spellbinder' sports immense blooms a full 4 1/2 inches wide on 18- to 20-inch plants. The entire bloom starts out a clear yellow, then the petals mature to a deeper chartreuse yellow, while the trumpet turns a creamy white. 'Spellbinder' features a light fragrance, too. It was first introduced in the 1940s.
A triandrus cultivar, 'Petrel' bears several 2-inch blooms per 12-inch stem, each a delicate ivory white with cups tinged palest yellow.