See and avoid/TCAS
I think I have had almost as many traffic conflicts/near misses/whatever you want to call them in TCAS equipped aircraft as I have in non-TCAS equipped aircraft.
Using the radio is rather fool-proof, though, especially when it's on the correct frequency.
By the way, if you happen to frequent Geraldton in WA, for christ's sake monitor and broadcast on 126.80 - new CTAF R frequency. I should be dead at the moment cause of a non-notam reading someone who decided that the right frequency to be on there was 126.70, when it wasn't.
520.