The green lightsaber was used by the Jedi Consular. They were the diplomats of the Jedi. Yoda wielded a green lightsaber.
Yellow Lightsaber
The yellow lightsaber were wielded by the Jedi Sentinels.They were about equally as good with a lightsaber as they were as good with the force. Plo Koon wielded a yellow lightsaber.
Curved Hilt Lightsaber
The curved hilt lightsaber Is a dueling lightsaber and a standard design of lightsaber. It is used with form2 lightsaber combat.
Blue Lightsaber
The blue lightsaber was used by the Jedi. It represented the Defender Jedi. Obi-Wan Kenobi had a blue lightsaber.
Purple Lightsaber
The purple lightsaber in the expanded universe can be wielded by anyone. Darth Bane had orange and a yellow lightsaber. In the movie universe Samuel L. Jackson got a purple lightsaber because he requested it from George Lucas.