I believe this bug was closed prematurely.  It is important to realize the unusual details of gnome-keyring-daemon, the services it provides, and its two-stage startup.  Take a look at the documentation:

http://live.gnome.org/GnomeKeyring/RunningDaemon

If you still think it should not be run twice, go back and read the documentation again.

Contrary to comment #2, it is spawned by PAM only when the user logs in by typing in a password.  When GDM is configured for automatic or timed login, gnome-keyring-daemon does not get spawned.  That means auto-login users will be left with no keyring service unless it gets started elsewhere.

When gnome-keyring-daemon is spawned by PAM, it is strictly to capture the user's password for automatic unlocking of the login keyring.  From the docs: "When run with the --login option, gnome-keyring-daemon does not fully initialize. It expects to be initialized later by calling another gnome-keyring-daemon with the --start option."  Yes, it does need to be run a second time, partly to finish initializing, and partly so it can print the environment variables that some programs use to find it.

Keep in mind that gnome-keyring-daemon acts not only as a place to store secrets, but also as an SSH agent.  Many people prefer it because it provides better keyring integration and better UI than the classic ssh-agent program.  In order for ssh and other programs to use it, the X session startup procedure must capture and export the environment variables it prints.  

For example, running gnome-keyring-daemon --start will finish initializing and print something like this:

  GNOME_KEYRING_CONTROL=/tmp/keyring-0vbOKZ
  GNOME_KEYRING_PID=1234
  SH_AUTH_SOCK=/tmp/keyring-0vbOKZ/ssh

In order to get full functionality, one of the X session startup scripts should therefore do something like this:  export `gnome-keyring-daemon --start`

Quoting from the documentation again:
"""
gnome-keyring-daemon has certain environment variables that must be set in the user's session:
    * Each of the above ways of starting gnome-keyring prints out appropriate environment variables to stdout.
    * In the case of --login only a few environment variables will be printed. A later call to --start will print the remaining environment variables.
    * When used with a modern DBus capable session manager (like gnome-session 2.24.x and later) gnome-keyring-daemon will register environment variables directly with the session manager.
"""

Under GNOME, I believe gnome-keyring-daemon gets its second run via the *.desktop scripts in /etc/xdg/autostart.  This completes initialization without capturing the printed environment variables, but since GNOME's session manager allows those environment variables to be set via D-Bus, they get exported anyway.  Under Xfce, the session manager lacks the D-Bus environment variable feature, so running gnome-keyring-daemon a second time via .desktop files fails to export the environment variables.  For now, on Xubuntu, it looks like it really does have to be done in one of the session startup scripts.

When I was using Xubuntu 9.10 (Karmic), I worked around the problem by putting this in a ~/.xprofile file:

  export `gnome-keyring-daemon --start`

That wasn't a good solution for most end users, but since I'm vaguely familiar with X startup details, I was able to figure it out.  However, it broke in Lucid.  It seems the developers recently changed libgnome-keyring to rely exclusively on D-Bus for communication with the daemon, ignoring environment variables like GNOME_KEYRING_CONTROL.  Since ~/.xprofile gets run before D-Bus is started, my workaround left me with a daemon that worked fine for older programs (like ssh), but could not announce itself on D-Bus and therefore could not be found by newer programs (like seahorse and nm-applet).

On Xubuntu Lucid, there are only three places I can see where starting gnome-keyring-daemon could fully initialize it, announce itself on D-Bus, and capture/export the printed environment variables for use in the X session.  Those are:

  /usr/share/xubuntu/session.sh
  /usr/bin/startxfce4
  /etc/xdg/xfce4/xinitrc

All of the above scripts are executed in an xubuntu session when launched by GDM, *after* dbus has started.

In summary, gnome-keyring-daemon could be really useful to Xubuntu users, but it won't be fully functional until the session startup runs it in such a way that it can both announce itself on D-Bus and export all its variables into the session environment.  I hope this can be done by default soon.  Until then, most users will miss out.