They look nice along the water's edge. Some of the swamp plants grow quickly, and will try to take over, when given the chance. I have posted a good tutorial on swamp plants in the Database. It covers the plants, and a 'how to' on building a bog. Swamp plants really add interest to your water garden.
Tropical lilies have the best selection in colors and types.
It is the only way to get blue and purple. There are night blooming types where the blossom opens around sunset and some have very interesting leaves. But, they don't like cold weather, and tend to become expensive if you live with winter. Those of you living in warm weather areas will get to enjoy these. I've posted a list of catalogs in the Database.