What are the most important elements/characters of Arthurian romances?

Arthurian romances are quite varied in their presentation of events, but there are several key characters and elements which are found throughout the Arthurian tradition. Thomas Malory's Le Morte Darthur is the most popular historical Arthurian text and provides the framework for most of what we know as Arthurian legend.
Arthur Pendragon is the king of Britain and head of the Round Table. He is given to Merlin as a child, who counsels him and guides him. Sir Ector raises him as a boy until he pulls the sword, Excalibur, from the stone and becomes king.
Guenevere is Arthur's queen. She is a passionate and romantic woman who falls in love with both Launcelot and Arthur. Her infidelity leads to the death of the two men she loves, and she later dies in a convent.
Launcelot du Lac is the greatest of all the knights. He desires to discover the Holy Grail, but he is unable to because of his adulterous love to Guenevere.
Merlin is the magician who helps King Uther Pendragon to sleep with the beautiful Igraine. In exchange, Merlin demands that Uther hands over their child to him. He then acts as a counselor throughout Arthur's life.
Mordred is Arthur's son from an adulterous relationship between Arthur and his sister. He is an evil knight who destroys the fellowship of the Round Table. He and Arthur kill each other in battle.
Camelot is the kingdom that Arthur establishes.
The Round Table is where Arthur and his knights meet and discuss problems. Since there is no "head" to a round table, no knight can feel superior to another. All the men are equal and must respect each other.
Excalibur is the sword which Arthur pulls out of a stone. After Arthur loses his sword in battle, it is returned to him by the Lady of the Lake. As Arthur is dying, he instructs one of his knights to throw the sword into the lake, where it is caught by an unknown hand.