Well, RMS made his storm, though i don't care for it. But one thing is true, Linux is just a kernel, GNU provides many of the tools that make it usuable, and then there are the distributions with their own special flavor.
So, the OS is not Linux, the kernel is. The OS is a mixture of the kernel and the tools, and possibly should reflect that. GNU/Linux sounds like Linux is a subset of the GNU implementation, whereas the average user might want to call GNU the subset of Linux, being they care more about the kernel. Thus, Linux/GNU.
The distribution cannot be ignored. Since they put it together, that is the "real name". So, when people ask me what OS i run, i can say "Debian". What flavor of Debian? To that one can answer GNU/Linux or Linux/GNU.
One thing about Debian, is that they seem to want to distribute any kernel, but with the GNU tools, so to them GNU/Linux may actually be more appropriate.
On another note, basically all distributions of Linux use the GNU tools, so mentioning Linux automatically infers both, whereas the opposite may not be true. Therefore, if one does not care but to answer the question, "Linux" is fine by itself.
What do you call it? And, what do you think it "should" be called?