As far as the question of "who needs more than 4gig of ram",
the answer is apparently "lots of people".
It was a pretty common request while I was working
in tech support. As often as not, it was people looking
for >4gig support per process, and at least with 2.2,
x86, and linux, that wasnt really an option. But it
wasnt uncommon for someone to want/need to be able
to malloc a half a dozen gigs of ram. And not just
malloc it, but use it as well.
But very often, people just needed more memory available
because of huge numbers of proccess running. Web servers
running on big hardware with long lasting cgi/asp/*let
proccesses were a common theme. Ie, a few thousand perl
processes taking a couple of megs each on a single
machine. Yes, people really do that.
Or perhaps, you just need to serve up several thousand
hits a second with a single machine. TUX and
32gigs of ram to the rescue... Okay, so I dont know
anyone actually doing that in production. But one thing I
in tech support, is if there is a limit on something in
someone will run into it.