Form Zero
Juyo
This form is almost entirely offencive in nature. Its main focus is in attempting to finish off it opponent at every opportunity and as such is a sort of anti-duelist form.
Palpatine, Mara Jade.
Vaapad
Force saturation form. This form borders on Sith technique as it utilizes continual energy flow from one’s own emotions and hence requires enormous levels of control in order to keep out of the Dark Side.
Mace Windu
Niman
Djem So
The point of this form is essentially to beat one’s way through their opponent’s offences and defence and hack them into little bits.
Anakin/Darth Vader and Luke.
Ataru
This form is nearly the opposite of Soresu in that its practisioner almost never holds still and throws presision to the winds, at least as much one can in combat. An integral part of this form is the use of augmentation from the Force and general acrobatics.
Yoda, Qui-Gonn, Darth Maul, and Obi-wan at that point as well.
Soresu
This form provides neigh impenetrable defences with lightning quick ripostes to utterly frustrate one’s opponent, while he’s still alive that is.
Obi-wan Kenobi, in Episode 3 to be technical.