Seems I despaired too soon about not being able to get good-looking fonts in Emacs. Thanks to Duncan Mak I've been able to compile and install an Emacs with anti-aliased fonts on Ubuntu. Here's the recipe:

Get the XFT_JHD_BRANCH of CVS Emacs, see XftGnuEmacs on the Emacs wiki, and this page from Deling Ren.

Get a further patch, from this mailing list post

Get the emacs-snapshot-debian directory from this arch repository and use it as the debian directory inside the Emacs source tree

Then I had to edit out the build instructions for the -nox variant of Emacs, as it didn't build properly, and to be sure, added this to the Emacs-gtk confflags section of debian/rules :

emacs_gtk_confflags += --with-xft=yes

After that, fakeroot dpkg-buildpackage -b in the source directory, and some time later, Emacs packages with anti-aliased fonts.

There are some limitations: you need to set the font in your ~/.Xresources file like this:

Emacs*font: Monospace-8

You may also want to fiddle with the Xft.dpi and Xft.hinting X properties to get the fonts to match your desktop environment.

OK, so it's a bit of effort, but worth it. Hopefully this patch will mature and make its way into future Linux distributions.