From a Christian perspective the use of talismans, amulets, or any of the sort is considered completely unacceptable. You will find Christians who make the sign of the cross, but the appropriate understanding of this isn't that the sign of the cross is some sort of talisman, it's an act of confessing our hope and trust in Jesus.
In what is perhaps the most famous Lutheran hymn (A Mighty Fortress is Our God) we sing this stanza:
"
And though this world, with devils filled,
should threaten to undo us,
we will not fear, for God has willed
his truth to triumph through us.
The prince of darkness grim,
we tremble not for him;
his rage we can endure,
for lo! his doom is sure;
one little word shall fell him."
That last line is vitally important, "one little word shall fell him", the "little word" is Jesus Christ and His Gospel.
Because we confess that Christ having died for the sins of the world has, by His resurrection, overcome and defeated all worldly power--sin, death, hell, and the devil. Thus the devil is defeated, struck down, conquered.
The traditional Orthodox Icon of the Anastasis (Resurrection) depicts Christ in Hades, His feet standing upon the broken doors of Hades and crushed and bound beneath those doors are usually one or two figures, which represent death and the devil.
The Christian has no need of charms, spells, talismans; not only because are these things inherently meaningless in and of themselves, but because the Christian confesses the victory of Jesus Christ over and against all principalities and powers.
The Christian looks to their baptism, for Lutherans the making of the sign of the cross is precisely that: a reminder of our baptism. Because we confess that in baptism we died with Christ and rose with Christ, were united with Christ, clothed with Christ. Christ is ours, and we are Christ's because of the grace of God, freely given us, which we receive in faith.
Making the sign of the cross doesn't mean anything in itself, after all we read in the Acts of the Apostles where several exorcists attempted to perform an exorcism citing "by the name of Jesus whom Paul preaches" to which the devil replied, "Jesus I know, and Paul I know, but who are you?". Because Jesus' name isn't a magical formula, and the cross isn't a talisman. What Paul had that the exorcists didn't have was faith in Jesus Christ, and the Holy Spirit alive in him through faith.
The devil is powerless against faith, by it he is crushed beneath our feet, and buried underneath the fallen doors of Hades which Christ has conquered.
-CryptoLutheran