I have a big kitchen strainer that fits across the bucket (although I usually need some help keeping it in place). It does a great job of straining. Once the hop particles start forming a layer it creates a natural filter to catch all those proteins and grain bits. I think it helps, at least making it easier to yeast wash, but I also don't think it's necessary.
I also use the strainer to aerate the wort. I dip the mesh about an inch into the wort and shake back and forth vigorously. Creates a huge foamy head of oxygen. I usually do that for about five minutes before pitching.