The Gurus are off on weekends, so I thought I would chime in on this.
I don't think it is really that the 5Bs are better for movies...It is that if you don't listen to music all that much, you will not be getting the extra sonic benefits that the 4T would give you. I believe it to be a bang for the buck so to speak. If you are not listening to music much, it would not be worth the extra cash, and you could move that cash into other areas of your AV setup, like a bigger sub!!!!
With that said, I have 4 5B, a 5C, and a 12D. Most of the music I listen to is concert DVDs. The 5Bs are no slouch when playing music. I have no regrets on my purchase. An added + is that the 5B was a better choice for WAF (not sure if that is a factor for you...Google it if you don't know what it is).
Remember that you have a 30 day in home trial, shipping included. Also, if you go with the 5B, you can always upgrade to the towers within a year of purchase for the price difference. However, you do pay shipping for both return speakers and new speakers, although Aperion can get you discounts on this. I would recommend that you get what you want upfront if you can, to avoid those extra costs.
Good luck on your decision. Regardless of what you choose, I know you will be happy with your Aperions!
Scottiemon