I think I remember seeing in one of the videos that if you press the power button when the screen is "off"(keypad locked as well?), the backlight turns on, and you get a large clock, with the message icons and whatnot. Maybe someone can confirm that. Not really a big deal to me, I think that the light may blink differently for different messages (voice, text,email), and as others have said, there are 3rd party apps for the clock screensaver.
EDIT: It was actually in the all about symbian review. Towards the bottom of the page:
"One other innovation for the E71 (and its stablemate, the slider E66) is that when the main display is keylocked and timed out, rather than a traditional screensaver appearing, the display blanks completely. "But I need to know the time!" I hear you say. Simply press and hold the D-pad and the time appears in large letters, as shown here. A much better solution than the old non-backlit, small-fonted solution."