Deadlifts, no question...also, be aware that if you have a gluteal dysfunction (which the vast majority of the population has, due to poor posture, compensation patterns, etc), meaning that you have poor neural activation of the glutes, it doesn't matter what exercises you use: you won't be able to utilize the glutes properly and you won't get the most benefit of the movement/exercise. Activation exercises such as supine glute bridges, hip corrections, single leg RDL's, etc can help this, as will appropriate mental focus.