I don't know what the fuss about mics is all about... I just get a pianist to play during the film!!!! You'll be wanting colour next.

On a serious point (which, being that I am a first time poster and only joined in order to post it, should probably have come first). I agree with all comments about the importance of the right mic (I'm not an expert but work in radio station and spend too long in the engineers den). But would add, don't just assume that the bigger price label, the better the mic will suit your needs. The SM58 has been mentioned, but as people have found, it is not ideal for video work, simply because the mic is designed to be used very close to the mouth. It is packed full of foam to muffle breathy pops and designed to cope with the dominant bass that close talking gives. A condenser rifle mic (with a purpose built wind shield) will give a much better result if the mic is just out of shot.

John