On the amp end I have ended up with bananas and spades, because I regularly swap amps and have to. These are gold plated copper bases with threaded ends so that I can easily change between banana and spade tips. I feel a bit safer when using the bananas (for reasons well covered already).
At the speaker end I use solid copper bananas. I made them up with twin screw ones, but threw one screw away and filed that hole with solder. My understanding is that keeping air away from copper connections (or silver) with solder, gold, or rhodium reduces oxidation/tarnishing.
However, I have never tried to hear the difference between plugs or bare wires in a system where all else is equal, so the above is only based on reading, not listening.