This is a very good question and lots of people will have a different take on what makes a good logo. That doesn't mean one is right and one is wrong. People just look at it from a different angle. For me there are five key things a logo has to be - memorable, simple, appropriate, easily recognisable and finally (and really importantly) your logo has to work over a variety of media types. MEMORABLE - people like familiarity, it makes them feel comfortable so a logo that is me