My preferred AR trigger is a two stage from ArmaLite. They have two versions, the tactical two stage with a 5lb break and a trace of creep. Second is the NM version, this trigger has a straight bow and is has 4.5lb break with no creep.
Both these have a adjustable spring position that changes break weight in three .5lb increments. The first stage weight is controlled by the trigger return spring and the second stage weight by the secondary disco spring position. Hammer hook controls how much creep you have.
ArmaLite has a great
article on tuning this trigger in the ArmaLite knowledge base.