After doing a lot of testing with different types of power cord and interconnect connectors, I do not actually believe that bare copper against bare copper would be the best solution. It really depends on what your speaker binding posts are. Bare copper against bare copper (two different pieces of metal under physical contact) does not really transfer higher frequencies as well. This is where plating increases the ability for high frequencies to jump from one piece to another (i.e. bare copper against rhodium/gold/silver plating). The plating just dictates the type of sonic signature you're after. Gold plated binding posts could be good, but if it's pure brass, then you can probably improve by using a plated banana/spade.
Correct way to attach speaker wires... Wait, what!!!
Okay this is going to sound ridiculous but I've always wondered if I'm connecting the wires in the proper way to the binding posts. I just picked up a Red Dragon S500 power amp and I figured I finally should ask the question. It has the screw down type of posts. Here is a link to the pic on their website. The wires I have are Mapleshade Clearview Golden Helix which terminate in a stiff single 3/4" wire. Any help for a dumb question would be greatly appreciated!