What should be my next upgrade? Speakers?

NAD NAD T-754 AV Reciever
Mitsibishi DLP WD-725 TV (only 1080i)
Denon DVD-2910 CD Player
Monster HTS-3600 AC filter
Klipsch RF-3 Speaker
Klipsch RS-3 Speaker
Paradigm PDR-12 Subwoofer

I just purchased the NAD reciever yesterday from www.audioadvisor.com. Have a Denon AVR-2801 right now hooked up. Hope the NAD is a sound improvement. What would you buy next? Go for better front and center speakers? Or go for a blue-ray?