I really like the drops with an infinite background. Graduated colour going back off into the distance leaving the droplet looking like it's alone in a giant pool.
How do you do this?
What you need is to have the light smooth and graduated and well dispersed behind the drop so that from most angles the water refracts the light back to the camera. It helps to have a spread of colours so that different parts of the ripples refract different coloured light so that the ripples have substance.
1). Make sure your drops are hitting your pool of water (pref something like a baking tray) near the middle.
2). Have a diffuser at the back (I use frosted perspex/acrylic)
3). Have your flashes behind the perspex with whatever colours you wish to try.
4). Aim at the splash site so that you are angled down slightly so the top of your splash spout is below the 'horizon' caused by the back of the cookie tray, leave enough space in front for a reflection.
Different effects can be created by using different setups.
1). One flash pointing down another directly on top of it pointing at the top of the diffuser, black dye in the water
2). One flash pointing at each side of the diffuser - Just plain water
3). One flash with gel, one without
To get reflections you need to have still water. I hold a cup under the stream of drops and let the water calm so it's completely smooth, trigger the camera and then move the cup away and try to capture the first drops hitting so the only ripples are from the initial impact. It takes practice!!
One final thing.. Any marks, water splashes or similar on your diffuser will reflect on the water and show up on your image. Keep it clean and out of the way of kids :)