Norse deities are of two groups: The Aesir and The Vanir.  The most important gods of the Aesir are Odin, Thor and, sometimes, Tyr.  The gods of Vanir are Njord, Frey and Freya.  These three gods joined the Vanir gods in the World of Asgard (Abode of the Gods) as part of a peace treaty between the gods.

Below is a list of these major gods (and the minor ones, as well) along with a brief description and a touch upon their legends.
 

Odin 
Known as the all father and ruler of the universe and of shamanic magic. A very difficult and demanding god that the people found hard to get close to. He is described to be tall, bearded, and one-eyed as he gave his other eye up as a sacrifice to be able to drink from the roots of the World Tree, Yggdrasil. To discover the secret of the runes (magic spells), Odin hanged himself from the World Tree for nine days. You may still hear many state "may the one eyed one be with you" a wish for guidance and wisdom in your travels.  It is known that he and his brothers, Vali and Ve, overthrew the giant Ymir and the giant’s remains were used to create their world.  Odin was often accompanied by two ravens named Hugin (thought) and Munin (memory). 
 

Thor
Personification of thunder and main god of war, second only to his father Odin .  Thor was the god of thunder. He produces thunder with his hammer, called Mjolnir which means "The Destroyer". This Hammer was made by dwarfs, and would magically return to Thor`s hand whenever he needed it.  Thor was depicted as a tall, muscular man with red hair and a beard. His magic belt could double his strength while his iron gloves protected his hands.  He was known to drink vast amounts.  According to one legend, the one that constructed the residence of the gods was the one that received the hammer. 
 

Tyr
 God of Government, Law and Justice, Oaths, Honor, and a very powerful warrior. An extremely powerful God, not for the faint hearted. 
Tyr was the sky god in Norse mythology. He sacrificed one of his hands for the good of the gods. In Asgard, the land of the gods, there was a demonic wolf called Fenrir. He was so huge and fierce that only Tyr would dare to approach him. The gods decided to tie the wolf up, using an unbreakable chain forged by dwarfs.  The wolf, wanting proof that the chain was harmless, asked that one of the gods put a hand in his mouth as the chain was slipped on. The beast was disappointed to find the chain could not be broken. Tyr had sacrificed his hand so that the gods could feel safer. Odin took Tyr's place as Sky god in legends somewhere around the eighth and ninth centuries. 
 

Loki
Loki was the spirit of strife and envy. Lord of fire and chaos, lies and trickery, Loki was acknowledged but rarely worshipped. A half brother to Odin, he is sometimes viewed as Odin’s "dark side". He may sometimes be depicted as the uncontrolled fire.  He has also been known as the ‘Lord of the Flies’. He possessed a pair of magic shoes that enabled him to walk through the sky earning him the nickname "skywalker". The son of a giant, he lived among the gods at Asgard, where he was always causing trouble but also aided them with his cunning, After he maneuvered the death of Balder, the gods chained him to a rock below a serpent whose mouth dripped venom.  Loki`s wife caught the drops in a cup ,but when she turned away to empty it the venom fell on Loki`s face causing him great anguish (and that, as some say, is what causes earthquakes).  Loki was to remain bound until the final battle in which he would lead the forces of evil against the gods.

Balder
Balder was known as the God of  peace and beauty. He was the second son of Odin and highly regarded by the Vikings, Balder was known as Balder the Good; he was the incarnation of beauty, justice, and gentleness. He had no faults and harbored malice toward none. Balder was the husband of the goddess Nanna and the father of Forseti, the god of justice and conciliation. He lived in a mansion in the sky called Breidablik (Broad Gleaming), a place where no unclean or evil thing was permitted.  After having a dream that he was going to die, his mother took oaths from all plants, creatures, elements and metals that they would not harm  him, all except the mistletoe plant for she felt it was too young and too small to harm  him. He was, therefore, thought to be immune from harm and the other gods, in sport, would throw things at him. Loki, the god of mischief, deceived Hod (Hoder), a blind god and Balder's brother, into throwing a spear made from mistletoe at Balder, thereby killing him. He is taken to Hel, and Frigg searches out Hella to find out what can be done to bring him back. Hella says that if every living thing will weep for Baldur, she will release him. Frigg is able to secure pledges from all living creatures except for an old woman named Thokk, who is actually Loki in disguise. Baldur, therefore, still waits in Hel with his wife, and will come out again only after Ragnarok to help rule the New World.
 

Aegir
Aegir was a fierce god of the sea. He had fingers like claws. His wife was named Ran, and they had nine daughters, the maidens believed to move the waves. Aegir would sometimes appear on the sea to destroy ships. Often, he and his wife would use nets to capture sailors, and take them down into his underwater kingdom. Captains would give coins to every sailor, so if they were captured they would have a gift for the gods. Saxon pirates would often sacrifice every tenth prisoner, ensuring a safe journey across Aegir's sea. Aegir was shown as a powerful god usually holding a spear.
 

Njord
The Norse god of winds, sea and fire. He brings good fortune at sea and in the hunt. Njord was the father of the twins, Freyr and Freyja, and was married to Skadi. They lived in Asgard as part of the peace treaty between the Asir and the Vanir.  Skadi was allowed to choose her husband from the gods but only by looking at their feet. Thinking she was picking Balder she choose Njord, eventually they split up and lived apart.
 

Freyr
Freyr was one of the group of Vanic gods. A very powerful fertility God. Usually depicted with a large erect penis, He is the god of peace and fruitfulness.  Freyr is also the brother of Freyja, the most popular of Goddesses she was a goddess of sexuality and basically a good time.  His parents were the gods Njord and Skadi.