Are you referring to banana plugs, spade lugs, and bare wires into the binding posts? Any one of the three is a reasonable choice, each with plusses and minuses. Banana plugs are very convenient. Spade lugs are less convenient, but provide a more solid connection. Bare wires are the "least pretty" (just the stripped ends of the wires inserted into the holes in the posts). Bare wires can offer the best connection (conductors directly in contact with the post), but also offer more opportunities for shorting the posts together with stray strands of the conductor. Spade lugs offer a connection that should be as good (assuming the spades are properly installed) and are easier to make sure there's no stray strands crossing over. Cheap banana plugs can loose the "springiness" that maintains the connection and give you a less solid signal path, but better banana plugs should not have that problem. Spades and bananas both need to be properly installed on the ends of the cables (no loose connectors or bad solder joints).

I use spades on the cables that I bought for my mains and center, but I have bananas on the surrounds for convenience.