The xscreensaver prompt doesn't match the Bluecurve L&F and uses an
ugly icon (the flame) with non-standard progress bar.  The look and
behavior of the gdm login prompt presented when you initially login
should be used at the xscreensaver login prompt for consistency.  

In fact, the user should never know that xscreensaver has been invoked
and is presenting this prompt.  It should appear that "the system" is
using one prompt throughout the user experience.  I'm not sure if this
is the right place to file this bug...

Steps to Reproduce:
1.  Lock the screen to invoke xscreensaver 
2.  Move the mouse to bring up xscreensaver login prompt