For the record, I don't think that TCAS, EGPWS, TSO'd GPS's and the like are useless gismo's. I am very familiar with their use and have used them often at work. However, they are tools to aid in situational awareness and to reduce the workload in a high traffic environment in IMC. (or in a TMA)
Mid air collisions aren't the big pilot killer. Poor attitudes and "press-on-itis" have killed more pilots than any thing else I know.
The best piece of safety equipment any one can have is situated between our ears. Good instruction with development of sound airmanship ideas is the best start. Proper planning. Knowing your limits. Effective use of the equipment you have on board. Strobes, radios, navaids. Continual development of your pilot skills whether it be a new rating or just going over old subjects should be a lifelong aim for all pilots.
Aviation isn't 100% risk free. Come to think of it, life isn't 100% risk free.
Have a look around next time you're driving on the motorway. How many folks are driving to the conditions? How many are being distracted by the car CD player, their phone, the kids in the back? How many are too close to the car in front? Have a look at how many aren't wearing a seatbelt!!
They may have the best air bags, the best ABS and the best tyres money can buy. However, a careless action on their behalf can render all of that useless.