I noticed that sometimes the lights under the 4-position center button flash in sequence, going around in a circle. I'm not certain what conditions make it do this, but it doesn't do it all the time. Outside of being another way to drain my battery, is there any use for this behavior? Is there any way to turn it off?

the circular flashes are a sms/missed call i believe..
a circular blinking light is email messages...

you may be able to turn them off in notifications...

I think it does a clockwise chase flash sequence for a missed call, counter-clockwise of the same for an incoming text and all of them flash a few times in rapid succession for an incoming e-mail.

I actually love it, when I see the flashing I know I missed something. It's great in meetings, in the movie theater and in general. It's WAY better than the stupid red and green lights on the 6700. I doubt it has a significant effect on battery life. I read all about it in the instruction manual , it is in the instructions about exactly what the lights mean.