Floodlights may be good for security, but not for aesthetics. There are many companies that make low-voltage lighting for around your garden. Some of the manufactors are quite reasonable in price. Check in hardware and nursery stores to find out what your options are. Underwater Lighting Lighting your garden with a light from beneath the water is a very dramatic effect at night.
Candles Floating candles, or larger citronella candles can add a beautiful accent when it is dark.