Why use banana plugs?

A new TV, receiver and PS3 are making me redo my "entertainment center/system" and I want to it right. I have a pair of JBL S312BE's I bought about 13 years ago. That's where this question comes from. I never bought banana plugs because I always thought they were all about convenience, but I never did know. The wire I use (there are other speakers now, but its all that original spool) is quality, 12 gauge, could be Monster but I honestly forget. Should I buy banana plugs? Do they make for better sound?