I have black skirts which are pretty cool to watch when you have a nice school. White skirts are feisty (not aggressive) and like to "dance with the black skirts"
I have also had neons with them but they dont really provide for a huge bit of entertainment besides their color.
Ive had serape tetras which are pretty cool, but im my experiance not as hardy as the others mentioned.
Zebra Danios are crazy little guys that i call the water dancers when you have them in a nice little school.
You could go platys or mollys if you want to see lots of babies