Rick, I really don't know where to start, this was like reading forum post from a Steam Train fan club....
Okay, lets start with the TV:
If you aren't going to pay too much for a Panasonic TV then buy Korean, they are the only ones really doing "value for money" these days and the quality of LG and Samsung is good. Most of 'the rest' are actually outsourcing to other companies anyway, so brands aren't what they used to be.
Keep your existing speakers, assuming they are in good condition and you paid good money for them, then just buy an AV amplifier or Home Cinema system, they don't cost alot these days. Take a look at the Onkyo TX-NR 515 or 525, they won't break the bank and are quite good (and they include an FM radio).
Get a slim Bluray player for less than $100, wouldn't hurt for it to match the brand of the TV you buy because HDMI-CEC will probably work (terrible interop) and will possibly allow you to control the player with your TV remote via the HDMI connection.
3D? Waste of money hype increasingly being abandoned. UltraHD? Too early, buy now and regret it forever. Expensive gold HDMI cables? Won't do anything for the digits. "Smart TV", TV manufacturers tend to abandon their products after they launch them so I prefer to think about external devices (like Roku or Apple TV) when thinking about adding internet functionality to the package.
I also ended up with Samsung...and now a Samsung Blu-ray player on order.....
I was disappointed with the Samsung compared with the Panasonic I had before......
Samsung at 1080 lines shows up the blocky artefacts, much more than the Panasonic did at 720 lines.
Everyone tends to compare specs at the top end of television picture quality but you actually spend a lot of time watching poor, low-energy pictures....so the TV that handles low quality best could be the way to go.
There might have been more smoothing on the Panasonic which isn't present on the Samsung. It might be worth looking at "sharpness" and "noise reduction". Remembering that blocking artifacts are more usually introduced at the origin and just scrubbed out at the receiver.
(For clarification: I am the CTO of CE software company Pixsan)
I agree with you about everything except the 720P. Go with the 1080P. And don't buy anything less than 42 inches. 45 to 50 inches is a nice size and reasonably priced. You won't be sorry. As time goes on, more and more stuff will be 1080P.
If you are looking at a Cable TV signal right now, it is compressed. So you are not seeing the full potential. I get my TV Over-The-Air and it is far better resolution than cable. You can really see the difference between stations that broadcast 720 vs 1080.
Most PBS stations are 1080 and the difference is definately noticeable. You can see what the station of interest is broadcasting OTA by checking out the call letters on Wikipedia.
Forgot to mention. Once you enter the station call letters in Wikipedia, if you click on the location coordinates, it will give you a Google map of the transmitter antenna location. If your home is within 35 to 40 miles from the transmitter, a modest antenna for less than $60 will work well. The non-amplified ones work the best. The amplifiers always seem to cause problems from overload.
I get my TV from over 65 miles away using a high-gain Yagi antenna that cost me about $50. It's up about 25 feet above the ground. The quality is HDTV all the way, no drop-outs and completely free. I get about 35 channels + Netflix for movies.
I like bobdvb's suggestions - keep your speakers, use one of those home theater setups and get a Samsung TV.
Stay away from the gold cables - the only gold there is your gold to them. Plain old copper was good enough for Tom Edison and should work for you, too (and it's better these days, anyway).
I went a little further myself but I had a lot of old and very nice speakers and some time to mess around - built my own amps using one of the many STA450 kits out there. Each amp has its own 'dumb' headless single board PC (and sucks power off their PSUs) with Ethernet and HDMI interface and I control them using one of the many free remote control packages available - all from this box. Sound in every room - differnt sound if I really want to confuse my (grown up) kids - and I run video off the HDMI outputs of the SBCs to big (and small) flat panel displays.
This works because I'm not interested in anyting on cable or broadcast TV - DVDs or BluRay is the extent of my interest, and those can be played over the network using VLC Media Player's streaming capabilities. Guess I could put a TV tuner thingus in this box and stream it - but what's to watch? Presidential debates? Meh.
And yes, I can get Pandora or whatever radio for my FM.
Although I'm past the biking/running phase (I like my knees they way they are, thanks) I still use my son's Xen X-Fi if I really, really, really need to listen to FM radio. Works fine. Lasts a long time.