"The Spirit himself is 'God's gift' par excellence (cf. John 4:10), a gift from God, and in turn communicates different spiritual gifts to those who welcome him." - Pope Francis
The greatest gift of the Holy Spirit is the Holy Spirit. The living God gives the gift of himself to those who are baptized. From the Spirit flows other gifts, some of which are for our personal sanctification while others are for the building up and support of the body of Christ. Many of the gifts are very familiar to us (wisdom, counsel, love) while others are somewhat foreign (healing, prophecy, tongues). Whatever our experience, the gifts of the Holy Spirit are for all Christians, and no one should think that the gifts are not for them.