In the darker, wetter months I use two rear and two front lights, but that's more about having a spare in case of crash, failure, battery issues or water penetration.
My rears are old Cateye (I think) units that have 2 rows of LEDs. I usually have one on constant and the other flashing.
My fronts are also Cateye, non-flashing. As a driver, I find flashing front lights an unhelpful distraction, but not rears. I have no idea why that is.
Until I read this thread, I thought it illegal to have flashing-only lights on a bicycle. If the law has changed, that is a good thing.
My main 'stay-alive' technique is one mentioned elsewhere on this and other threads: I look at other cyclists and see what makes them more visible.
Lots of TdF yellow and Giro pink seem to help.
I toyed some years ago with big headlamp things whose rechargeable battery sat in my cage, but they were just a hassle. Super for an hour or so, but hard work to keep in tip-top condition for a 70-minute commute each way.
I'm back to LEDs now.
Another safety device is to ride a bicycle on which you are comfortable and which you are accustomed to riding. It's extraordinary how many wobbly, jittery, apparently terrified 'mobile chicanes' one sees out in public on bicycles... unsteady when indicating, too nervous to look behind themselves more than once for any change of lane or direction... and it's often only the most token glance. If you are on a machine on which you feel at home, comfortable, stable, secure... then you will be much better able to adapt, react and ride in a way that will bring a much lower wallop-to-mile ratio than if you are a petrified-looking wobble-monster.