I think I say perfume BOTH ways.
I have always used the spelling of grey, even though I was pretty sure its the Brit version. I blame the heavy addiction to Tolkien in my early years. Gray just feels wrong.
This is what I was taught at theatre school. Firefox doesn’t like it when I spell it that way though. In my head I make the distiction, and actually know of one theatre company that performs in the “Theatre Theater” which I always thought was a rather clever name for a theater.
I also always think that gray looks odd. I tend to spell it grey (which again, firefox tells me is wrong. But then it also tells me that firefox is wrong, so what does it know.)
Calling a cinema a theater drives me crazy. It’s not a theater; it’s a cinema. Perhaps in the early days, they used theaters for cinemas and so that’s why were’ stuck with the word. I know, I know, common venacular and all that.
Note that there are a number of usages where both forms are perfectly OK. We just have to get used to the fact that sometimes there is no “One True Right Way”, no matter how it confuses us or annoys Mrs. Thistlebottom.
Grey/Gray is one of those.
I tend to use “gray” to describe something depressing or boring, and “grey” to describe something nifty or special. Because “grey” is just inherently cooler than “gray”. I suspect, however, that this is a personal quirk. 
Here in Okieland, PERfume seems to be a more rural usage, with perFUME being more urban. They’re pretty interchangeable, though.
Other than the Gray code which comes from a name, I refer to the colour as grey.
British usage? wikipedia seems to think so…
Not entirely. In clothing the term seems to be grey more often than not. Especially in men’s suits, where a basic Anglophilia never quite goes away, you see Oxford grey and Cambridge grey most often.
The Man in the Gr_y Flannel Suit, however, seems to be undecided.
BTW, that suit is Oxford, slightly lighter than medium gr_y. Cambridge is dead medium, a 50% gr_y value.
I always say per-FUME. I wonder, does this pronunciation difference correlate with the way people say “insurance” or “umbrella”? I.e., stress on the first syllable or the second?
Interesting. Before this thread, I had never realized that some people differentiate between spellings of “gray/grey” based on the context of the word. To me, “gray” and “grey” mean exactly the same thing in all cases, and which one you use is a matter of which one you’re more used to seeing. I tend to vacillate between the two, with perhaps a slight preference for “grey.”
I do this, but never thought about it before reading this thread. I’m american.
Hmm. . . I think I use perFUME and PERfume in different sentence structures. . .
“It’s a new brand of perFUME.”
“What brand of PERfume is that?”
I think it depends upon the rhythm of the sentence somehow.
And I think I use “grey” more that I use “gray”.