Hi, I'm new to photography, and I'm just thinking about buying a new filter. I'm interested in shooting landscapes, and beaches in particular. From what I can tell, most people say that a polarizer is essential, but if I want to shoot sunsets, would I be better off with an ND grad? Or if I want to shoot a sunset with waves on rocks in the foreground at a slow shutter speed do I need a normal ND filter, so that the foreground isn't too bright (or would this only apply in bright sunlight (or not at all??))? Sorry about the barrage of questions, thanks in advance!