I browsed through the default set of screensavers and the most are ugly, a couple are decent and the only quality ones are Flurry, GLSlideshow, MetaBalls are PopSquares. Where does one find more nice screensavers for Xubuntu? APT repository or xfce-look.org doesn't seem to have it. Or would you recommend running gnome-screensaver instead of xscreensaver? What options are there so that my screen doesn't display rough (not antialiased) visualizations of mathematic obsessions?
Have you added the following packages using Synaptic Package Manager?
These are the screensaver files themselves. For the rss-glx screensavers, please read the documentation in
/usr/share/doc/rss-glx to properly install them into xscreensaver.
I recommend you give electricsheep a try. Looks nice, IMO, but be aware that over time it will build up files in the ".electricsheep" folder in your home directory.
sudo apt-get install electricsheep
Xscreensaver is a dated application and you would not find too many good good looking screensavers for it. I would personally recommend that you use gnome-screensaver. Look here if you have any problems.