When I was in Ireland, probably in 1980 or 1981, I was told that "You're welcome" (as an answer to "Thank you") was typically Irish, and American too, but not British.
I had also read (in an old grammar) that the English usually don't answer when one thanks them, but simply smile; only if they want to be excessively polite, they say "Not at all" or "Don't mention it".
Is that still true? Do the English say "You're welcome" too, nowadays? And: only some Englishmen (perhaps those who like imitating americanisms) or even the well educated, linguistically conservative (which for me means the best) speakers?
Is it (still) possible to say "Not at all"? or "Don't mention it"? Or not to answer at all and just smile?

Thank you for your answers. (What will your answer to my "thank you" be?)
All of the greetings are fine to me. They have basic greeting, formal and informal. It depends on different situation. "You are welcome" is safe usage that you can apply to almost every ocassion, it's polite usage. "Not at all" and "Don't mention it" seems friendly more or less and distance between two parties is closer.

You can also say

Sure thing. Or simply "Sure".
My pleasure.
No bother.

This will be my response to your post.
It's a pleasure to have been of some assistance.
Just smile