date Posted: Dec 28, 2005 1:04 PM
Luke wanted to save his father. Anakin wanted to save Padme. Both of them relied on the Force to achieve their ends. The difference...love and sacrifice.
Luke was willing to sacrifice himself to save his father, someone he loved. He was not willing to sacrifice his beliefs in love and life (read: will of the Force).
Anakin was willing to sacrifice everything, his beliefs, his friends, his teachers, everything but himself, for his wife, someone he loved. Anakin was unwilling to take the step he most needed: trusting in the very 'Force' that brought him to life.