Say you have my currents setup. What do you upgrade??

[lojack1976]

If you swap out the front left and right then you should also swap out the center to match them up. Whether you go for the Polk, JBL, or Infinity towers you will need to get the appropriate center to match. You should audition each of those speakers with some of your own music to see which sound you like the most. All are quality brands, but everyone has their own tastes. The guy trying to sell you those speakers may like one set over the ones you prefer. His tastes may differ from yours. The only wrong option is the one that leaves you with speakers you don't like. Its also a good idea to demo those speakers with the receiver you will be using. Some speakers match up better with certain receivers than others.