I'm creeped out by all the sound devices on this forum.
There are only two things I like less than speakers on bikes - speakers on kayaks, and headphones on bikes or pedestrians.

My '98 Moser is the quietest bicycle I have ever ridden. Even the tires barely whoosh.

Otherwise, I'm all for lights, front and rear, helmet blinkies, bike bells and stuff that makes us safer.
I always run my headlight solid, because it's rude to blinkie at pedestrians.
Run my tail-light solid in the dark (adding helmet blinkie) and run the tail-light blinkie in the day.
I have front and rear blinkies on my Metro helmet.
I mostly use them as signals - only turn them on when I want an extra measure of notice from motorists.
I've found turning on the front helmet blinkie makes drivers, who need to, recognize when you have the right of way, and otherwise, when you look straight at the driver, you will recognize from his reaction what he is going to do, be able to anticipate his next move, and plan yours.