pretty much any party i'm not at is a great party...
a great party is where the attendees of the party are comfortable... and are able to enjoy themselves... No matter what the event happens to be... A good host makes sure that their guests are comfortable.
Over the years, i've watched my party animal parents at their own parties and at other people's parties. They are excellent hosts. They take the time to greet each guest. Bartender dad, makes sure that they have a drink in their hand, they will introduce them to other people, if they see someone being quiet, they will do what they can to engage that person... (I don't have those skills)