In my school and university I was taught to say "Not at all" or "Don't mention it" in response to "Thank you!". Now I rarely hear these phrases used, but rather something like "You're welcome", "It's OK", "My pleasure", or "No problem".
My real life conversation experience is very poor. I often listen to some English learning podcasts, and watch some films in English. So I listen to dialogs, which are probably not from the modern real life world.
How do native English speakers tend to respond to "Thank you!" now? What I should care about, when choosing from the available options?