Where is Gnosticism in the 21st century? Where it's been for the past 1900 years, in the hearts and minds of radical fundamentalist who hate humanity. Fundies, like Gnostics, hate the "flesh". They believe the flesh of humanity to be the enemy of God and to be everything wrong humanity. Just as the Gnostics of old imparted "secret knowledge" to those willing to listen, knowledge that taught them how to escape the material world and be freedom from the flesh, fundamentalist do the same today. They teach doctrines the denies the humanity of Christ and speaks of Jesus as if he's some Spirit trapped in a dirt bag. I admit there is much talk in the letters of St. Paul admonishing us to refuse the flesh and calling us "clay jars", but St. Paul is expounding on the mortal nature of our existence. St. Paul is also the one who whole heartedly believes in the bodily resurrection of the dead and without a body there can be no resurrection.
The Jewish tradition that Jesus and then St. Paul came from values humanity and saw humanity as an extension of who God is. They valued the body and saw salvation as holistic, not just spiritual. God is redeeming our bodies for eternity, not just our spirits. The truth is, if what we believe and profess about Jesus is true, than God is human, or at lest humans are like God. God has a human body, human emotions and so on. Or perhaps what Jesus did for us was to point out that God can dwell in us all and with God his reign of justice and peace. Either way, our bodies are not bad, our humanity is not bad, our nature is corrupted and Christ came to show us that it can all work together for the glory of God. Jesus said he was the way the truth and the light, and he alone is the way to God, or at lest his way of living is.
Jesus demonstrated that humans can be perfect, that we can exercise what John Wesley referred to as, "Christian perfection". In order to obtain this status of perfection one must first be a Christian, profess faith in the way of Jesus, and second love others and themselves. Fundamentalist don't love others and I'm not sure that they even love themsleves. All their self loathing and self hatred, all their denial of the flesh, instructing youth and especially young girls, that their bodies are somehow evil, that the natural feelings and experiences they are having are evil and that the only thing good is reading the bible and praying...this is so anti-Christ. Jesus taught us away to live that embodies everything godly about ourselves (about our original state), and he showed us that not just our spirits, but our bodies will be redeemed through the resurrection. It's regeneration, the new creation all possible through faith in the way of Jesus. Our bodies are not bad, our flesh does not need to be destroyed and salvation is not release from our bodies, but instead wholeness with it.