My setup

Home Theater

Mitsubishi 82" DLP
Kenwood VR-4080 Reciever (.003 THD)
BIC PL-66 Acoustech Speakers
2 Audiosource SW15 200 watt Subwoofers
Sony BDPS-570 Blu-Ray Player
HTPC Media Center 7
Terx Amplified Antenna

I am thinking of adding Pl-76 Towers

BIC Acoustech PL-76 Tower Speakers BRAND NEW VERSION

since my reciever has A and B outputs. The PL-66's are in a wall unit about 6' high and they sound great.
I listen mostly to Jazz Vocals and movies, hard classic rock once in a while.
I wonder if adding the towers will make that much difference?
Any advice will be greatly appreciated.