Longhorn isn't an actual product yet, so it's kind of hard to call it "marketing". "Chicago" became Windows 95, "Cairo" became Windows 2000, "Whistler" was released as XP - I don't expect "Longhorn" to be the actual release name. Given that, I can't see that really going anywhere.
I disagree. Microsoft is actively marketing Longhorn to software developers. Watch this week's WinHEC video - it devotes a large amount of time to promoting Longhorn. I don't recall that Microsoft giving as much publicity to the Chicago or Cairo code-names.
My operations are running well on Panther (the current version of Mac OS X), so I didn't plan to stand in line this weekend to get Tiger. But I may have to do that now, before the injunction hearing.
I hope Apple abandons the use of cats and Roman numerals to name their operating systems. Just having a computer company named "Apple" is enough of a marketing problem. But despite the silly names, they do have the superior products.