New tv, Should I upgrade my receiver

I just upgraded my TV from a Samsung 50" dlp to a Panasonic 54"plasma. The differance is great. My question is should I upgrade my receiver. My current box is a Yamaha htr-5660. This reciever is in good shape but has no HDMI and is a 6.1 channel. So what advantages am I missing with no HDMI. Right now I have two good front speakers, and real good center speaker. My rear speakers are KLH metal boxes ,I think they were free. I know I need rear surround and sub woofer speakers, But what about the receiver. Great TV, Blu -Ray is it time to upgrade?



thanks Ron

you will get much more improvement by upgrading the rest of your speakers. Just adding the subwoofer will add more dynamic effect to your listening than audio over HDMI ever will alone.