I have recently noticed the surge in popularity among dati leumi youth and yeshiva bachurim to grow long peyot. What is the reason for this? Is it more cultural than religious? Also, is it a sign of non-conformism? Is this not a generally chasidic minhag anyway?

This question should be properly addressed to a sociologist, but as a layman in that field I will attempt to at least present my observations. The populatity of peyot, along with the heightened interest in Bratslav and Ishbitz, indicates a search for personal identity in service of HaShem, as opposed to the communal focus that has been the hallmark of the dati leumi community in the past forty years. ((Actually longer, but the 6 day war clarified this focus). There is an element of non conformism, or teenage rebelion, in peyot, but that is certainly not the main point. All adolescents rebel in one way or another, the issue is how and to what degree. The peyot revolution is part of an attempt to find personal meaning and satisfaction in Torah and mitzvot, and come together with the music and dancing, the Carlebach davening, the attachment to hilltop settlements, that are all part of the search for personal identity. I should add that for many, the points I mentioned above are not in opposition to learning Torah and care in halachic practice. It remains to be seen what the long term effect of these phenomena will be on the dati leumi community.