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?
Best Answer
In common conversation in the US Midwest I rarely hear "Not at all" or "Don't mention it." "No problem" is very common, and "You're welcome" is also pretty well-used.
My personal usage:
I use "Not at all," "Don't mention it," and "No problem" when the activity I'm being thanked for was really no big deal. I use "My pleasure" when emphasizing that I'm happy to be of assistance (often in a customer service context), and "You're welcome" when the action prompting the thanks was a little bit of a bother. In essence I use different phrases to indicate how "thanks-worthy" the activity was.
That's probably not common usage, though.
EDIT
I think I misrepresented what I originally meant, so here's a little clarification.
If someone thanks me for something I always do (for instance I always cook dinner in our house) then I would say "No problem" or "My pleasure" depending on context. If I did a chore that was someone else's responsibility, I would say "You're welcome" even if I was happy to have done it, because it took an extra effort on my part, not because it was a "bother."