I believe that one cannot receive Christ apart from the work of the Holy Spirit and thus does receive the Holy Spirit in this sense when he or she accepts Jesus as savior. The ideal would be for us to teach clearly about the Holy Spirit when we accept new believers into membership and thus we could see the salvation and baptism in the Holy Spirit occur right at the beginning.
At the same time, the Christian life is one of growth, and one can have many further experiences with the Holy Spirit. The fact is that many Christians live without an awareness of the power of God that is available to them. They need to come to know the power of the Holy Spirit.