> Xfce hasn't actually been lightweight for years, unless it's improved
recently (my only experience since around 2004/5 has been Xubuntu, which
is a bit of a pig).
When I last used Ubuntu, it's base system was pretty large. It had many
large daemons (done in Python, Perl...) running which I didn't need or
even didn't have the hardware (Bluetooth etc). So it might not be Xfce or
Xubuntu issue, but inherited from the Ubuntu base.
In Gnome desktop main memory usage (before you start any apps) seemed to
come from out-of-process panel applets, I guess that's a problem with
Xfce too. (Out-of-process applets are a reliability measure as in-process
applets can crash the whole panel if they have bugs)
 UI app(let) memory overhead is surprisingly large. They load a huge
amount of shared libraries and each library adds to the overhead. There's
private font, locale and theme data etc.