Comment 5 for bug 947547

The username on the top left is also difficult to read. On light gray wallpapers it practically blends into the top bar. I submitted this as part of a bug (Bug #1042417) but it was just marked as a duplicate of this one. Shouldn't be too hard to fix; the time on the top right of the screen is much more readable, so if the formatting of the username is made to match that of the time, it should look much better.

As for the readability of 'Guest Session' and the logo, perhaps you could put a shadow behind those to make them stand out from a light background.