"I would like to use the TV's speaker for my center channel. I have a JVC receiver that has a coaxial preamp center channel and the TV has a coaxial connector for center channel. Is that how I'm to pull this off? "
STOP! That is an RCA input- standard analog speaker connection, not a digital coax connection. You would connect your receiver's center channel out there. Read The Fine Manual, page 58. I think you'll decide not to use the TV as a center speaker. If you ever listen to surround sound music with the TV off, you won't hook up the TV as center speaker- it won't work w/TV off or without a video signal.
"Is it possible to connect my HTPC via HDMI to the 61Z786? "
JVC says no, no support. Others are doing this, or trying.
"What is exact resolution and frequency I should be trying to match so the TV will recognize the signal?"
Welcome to the bleeding edge and ALL the fun there is to be had as a pioneer!
I have connected my laptop using the VGA connector, set to 1024x768 @ 60 MHz. I'm quite happy with the results. The 4:3 ratio on the screen is fine and it is quite usable for word processing and surfing. I'll attach a word processing example below.
I have learned that my ability to take a closeup macro shot of the TV screen is somewhat lacking. I'll have to practice more to get usable shots. Plus, I currently have to angle the camera up a bit on it's tripod to take photos.
I'll sort thru and maybe post a few more, or learn how to get a very close up shot of the CA, if that's what it is. I must emphasize, it's only about a pixel or so wide and certainly is not visible while watching. I'll try to get a better focus. And some shots make the magenta on the screen look blue. And some shots show color artifacts that aren't there by eyeball.
It appears to me that the 4:3 image sides are bowed, so I checked with a straight edge. On my set at least, they are not bowed, it's my imagination.
Ken Golden, your review was dead on. Certainly a better set. And if the 1080s are even better, great. For those with the cash. If I waited for a 1080, I'd go with the 70" model for the size and memory card slots. And that, I figure, would cost me about twice what I paid for my 61Z786. I'll bet a 61" 1080 will cost $1200-$1500 more than my 61Z786.
I've done more comparisons of the JVC tuner and the ATI HDTV Wonder tuner in my HTPC. It seems the ATI is in fact the better tuner. I can sometimes pull in 30-1 & 30-2 on the ATI but not on the JVC. So far, I have never received either station on the JVC but not on the ATI. These are not stations I watch and are not always available anyway.
I'll try to get to answering other questions later on, maybe tonight.