TRL, I'm all for safety features. If the life-saving benefits of DRL have been actually proven then auto manufacturers should employ them by default. However, they can also learn from this forum/thread that there are situations where they can be dangerous. This danger can be reduced by providing fully automatic lights (as in my other vehicle), as well as an override switch for those times when they are more of a nuisance than an accident preventer.
I also don't believe it's of value to leave your light switch on all the time since the taillights will be lit up possibly causing other drivers behind you not to notice that you have applied the brakes - thereby potentially causing an accident. People tend to not "see" what they get used to.