I'll disagree that Desktops will go away any sooner than laptops;
That is, until desktop computing is fully migrated over to our HDTVs. Not everybody games on a console or does photo editing on a laptop; there are some tasks that simply need a larger screen dedicated to computing which, while an HDTV can do it, they're actually too big for individual use. Desktop computing will be around for a long, long time. The form factor itself will likely change many times before optical displays are no longer needed.