Best safety equipment

light yourself up like a christmas tree, and wear as much reflective stuff as you can!

there are a thousand choices in all price ranges for lighting.  Some of the Cree T-6 "magic shine" style lights on ebay are dirt cheap (like $25) and super bright.

Or- you could do all your riding on a trainer.  they're safe (blah) 

Brain first and best yes.

Next best for dusk is a bright rear blinkie that's powerful, like a Planet Mars 3.0 or PB Superflash. 

I wear a reflective lighted vest similar to this when running (ETA - even during daylight hours if I'm in a high traffic area) :

I don't ride in the dark, but even during the day, I always try to wear contrasting colors that stand out.  Most people seem to like outrageous designs for their cycling jerseys because they're cool.  I like them because it's more visible.  This is one of my favorites:

Biking - front and rear flashing lights that are bright (Blackburn, I think) and typically a brighter jersey, like with red, yellow, etc. graphics, bright yellow brain bucket.  Running - Nathan vest with 360* reflective striping, usually a headlamp (when it's dark) and reflective bands on my ankles.  I don't want anyone to try to use the excuse, "I didn't see her".  Swimming - I don't do open water swims too often (other than races), but when I do it's in an area where boats can't go and I wear a bright cap (orange, usually).

My favorite nighttime product is this:

http://www.amphipod.com/products/visibility/ledslighted-bands/xinglet-flash-led

I got it for running, but I also have worn it biking. I loosened the straps and fit it around my backpack even.  It's SOOO SOOO easy to wear, totally worth the money.   I've had other reflective vests that can get sweaty and don't have the lights built in.  This is the best.

High powered lights.  Not just the cheap stuff...invest in the USB rechargable lights that are usually locked up in the glass case at the LBS.  I use a 60 lumen tail light that cost me $60 for commuting.  I know I have a good light when other cyclists I bump into while commuting to work tell me that they absolutely cannot ride behind me because my light is too bright.

You need a light that pops out to drivers given the other lights in their vision.  Other car tail lights, traffic lights, street lights, houses and businesses on the side of the road, etc.  If you're using a $20 light you got off the shelf...chances are it's not going to stand out...and a driver will only see the light if they already saw you as a cyclist first.