The use of buffered streams in Java has come up a few times on ##java recently, so it might be worth reading something that one of the channel residents wrote up about the topic late last year: “The reason to use a buffered stream in Java.”
Aside from being generally useful information, it actually has a test; the conclusion is that using a buffered stream is usually wise because it helps avoid system calls. The test shows this by spending four minutes making system calls, and only one and a half minutes in the actual program code.
Well done.