I like this Hyacinth Bulb Centerpiece as shown on Martha Stewart Weddings
Apparently, bulbs generally cost less than cut flowers. Plus, the centerpieces can be made ahead by pouring a layer of small stones into a clear vase, and placing the rinsed bulbs in the stones so that the stems stand upright. A few days later. the bulbs will bloom. Their tip is to use warm water to open the petals, or cold water to keep them from opening too fast.