In my opinion, after i blocked the hildon rotation with "Orientation Lock" my battery's life seems at least DOUBLED!!

Could someone confirm this behavior?

I wouldn't say "doubled" but there is a noticeable improvement.
It also depends what else you have installed or setup.
Widgets, Kernel Power and SmartReflex, etc.

If you don't require portrait it's better to have it locked.

Come to think about it.
It mainly depends how much you rotate the phone with the screen unlocked.

...to me, 4 days without rotations are better than 2 days with rotation... (you know, when the battery becomes empty there is something else that keeps rotating, not only the phone...)

.... the strange think, is that this should not happen because no one spend the day rotating the phone and while in standby this should be disabled.

Until now, the only issue i have found is that receiving a call while in standby makes appear the dialer window without the hangup button...

LOL

(10 char)