I have a Sony46S3000.

Since it is 720p will an upconvert DVD player improve picture quality
or it a waste?

Right now I am running my 5 yr old Pioneer DVD player (DV-444) and the
picture is alright but not spectacular.(component).

There is a Sony DVPNS77H for $100 at Sears right now and I'm
wondering if I should pick it up.

Another thing I was wondering is I previosly had my 5.1 system
hooked up and ran the dvd player through that. However I now
have to run the player dirctly into the tv because my "only" 5
year old Pioneer Elite receiver has no HDMI or component inputs.

How do I get my DVD player to push sound back into the receiver
if I am running HDMI from DVD player into television?

Thanks for any help!

I have a Sony46S3000.

Since it is 720p will an upconvert DVD player improve picture quality
or it a waste?

Right now I am running my 5 yr old Pioneer DVD player (DV-444) and the
picture is alright but not spectacular.(component).

There is a Sony DVPNS77H for $100 at Sears right now and I'm
wondering if I should pick it up.

Another thing I was wondering is I previosly had my 5.1 system
hooked up and ran the dvd player through that. However I now
have to run the player dirctly into the tv because my "only" 5
year old Pioneer Elite receiver has no HDMI or component inputs.

How do I get my DVD player to push sound back into the receiver
if I am running HDMI from DVD player into television?

Thanks for any help!
I have a Denon receiver with an Oppo 981. I disabled the HDMI sound. I run a digital coaxial cable from the DVD player coax output. Make sure your receiver has a coax input. Also make sure that the coax input is assigned to the DVD player. If your receiver is DD or DTS capable you will enjoy both sounds. If your DVD player is SACD or DVD-Audio capable follow the DVD player and receiver connection instructions. This should help.

I have a Sony46S3000.

Since it is 720p will an upconvert DVD player improve picture quality
or it a waste?

Right now I am running my 5 yr old Pioneer DVD player (DV-444) and the
picture is alright but not spectacular.(component).

Improvement is possible, but unless the old player is really bad you will not see a night-and-day difference. It depends on your viewing habits. It is easier to justify the expenditure if you are fanatical about your DVDs.

I don't know about your Pioneer 444, but the 434 got a dismal review here:
http://www.hometheaterhifi.com/cgi-bin/shootout.cgi?function=search&articles=all&type=&manufacturer=21&maxprice=0&deInt=0&mpeg=0

-Bill