For me, it's a reminder to question the nature of authority and a harsh lesson in valuing religious freedom. There's considerable evidence Fawkes and the others were framed to create a reason for a new wave of anti Catholic hysteria.
James I was not a big supporter of civil rights, not that anyone in his day was, but his refusal to hear any religious petitions or criticisms and continuation of Elizabeth I's policies were a damn good reason he should be blown up. Fawkes, despite what else you can say about him, was not a perfect man, but he stood up for his religious freedom. That's balls. That's the kind of balls I hope I'd have if someone ever tried to ban my religion.
It makes me very glad we have as much religious freedom as we do when I think about Guy Fawkes Day. While it was certainly not have been Fawkes' intention, I sincerely believe his actions contributed to the development of this by showing what happens when you try to force a state religion.
Also, just on the side and really it's a coincidence, James I wanted to unite Scotland and England, something my ancestors allegedly opposed FWIW. My ancestors (in a later century) were also pressured to leave Scotland because they were the wrong religion according to the government at the time. They'd be proud of Guy...
