The waterfall style of counter top has a rounded top edge and straight bottom edge on the side of the counter top. It appears that the laminate is running over the edge like a waterfall and the underside is left unfinished. This counter top style is a "post-formed" counter top, meaning the laminate was heated, making it pliable, and then wrapped around a form to create the shape.
If you do not like the idea of leaving part of your counter top unfinished, consider the bull-nose style. Bull-nose is also a post-formed laminate that is rounded and the underside is finished.
A standard beveled edge is designed to make your laminate counter top look like a granite or marble counter top. Standard beveled edges are virtually seamless and can be mixed with contrasting colors to create an authentic look.
Full-front edge molding creates an opportunity to create a rounded edge using a wooden beveled strip of molding. The laminate-wood mix creates an interesting contrast, and the wooden molding can be sculpted to create interesting effects. The molding can be milled so that is forms a variety of rounded, decorative edges.