While the backlight is one of the more energy-hungry "applications," I dislike having to fiddle with the screen timeout, making it short enough to have a positive impact while still being able to read a full screen of text without touching the screen to bring back the backlight. I really like the app Screebl; it's free but you can buy the professional version. The paid version doesn't really do anything more or better but it's so useful I wanted to compensate the author. Screebl watches the accelerometer and knows when you have the phone angled in a normal-use reading position, horizontal and vertical, and keeps the backlight on in those positions. You can alter the parameters for those positions. Go outside those parameters or lay the phone flat down and the backlight goes off in 15 seconds.