I don’t think most people these days know that Linux is only a kernel.
I mean, sure, its great that GNU/Linux (that is, GNU *plus* the Linux monolithic kernel) has been ported to so many devices and hardware platforms, but I think that that’s probably the (or a) basis for the reason(s) why you won’t be hearing about a single “killer desktop distro” coming out of the GNU/Linux platform anytime in the near future.
Because GNU/Linux was not made for the common desktop from the onset, we’ve only seen a recent spate of GNU/Linux distributions which have been aimed for that particular audience, which is currently dominated by Windows and Mac OS X (both of which have long scored with hardware. UPnP, anyone?). Plus, because there is such a plethora of distributions already (which should go without saying for the desktop-oriented distros, such as Ubuntu), desktop users will have a hard time figuring out exactly which one they would want to try out. After all, probably the vast majority of Windows users aren’t geeks who will take time to even install software at any rate (like my oldest Sis, although its understandable since her ex-husband lent an HP Pavilion to her and because it has only a tiny bit of RAM).
Frankly, if there is going to be a large-scale collective movement of the GNU/Linux operating platform to the desktop/laptop, they’ll have to withdraw from the longstanding stereotypes and barriers which have hindered such efforts in the past. I’d actually say that the Desktop/Laptop GNU/Linux distribution which could make the largest killing on its target area will look, act, and feel alot more different from the present-day Ubuntu.
Maybe its Symphony OS? Or what about ELive?
Maybe even one that natively uses Sun’s Looking Glass Project?
I dunno….give them a few years to develop and we’ll see.