What is an HDMI input?

Sorry to have to ask this "chowder-head" question! But for a variety of reasons, I spend my money on 2 channel gear, and my older Pioneer rear projection non-HDTV [50"] serves my needs quite well. In fact, I still play primarily laser discs! Video doesn't get my "Ya Ya's out" like audio does.
A HDMI input is a "high def" input that includes audio - the older DVI was only video.
Using a HDMI input allows you to go digital out on the cable box or DVD player directly digital in to the TV, bypassing the analog transfer if you go any other way.
It also adjusts the aspect ratio of the picture automatically, a very nice feature.
Yup,hdmi and dvi are just for the newer HD tv's. Dvi is video only; hdmi is video and audio in one cable. The objective is to keep the signal digital from source to display.That means you must have a dig. tv.
Aspect ratio and resolution!

You are not alone,I need to catch up on this home theater new staff as well.I am a two channel guy also.Guys thanks for the explanation,I had no clue either.
Hdmi is the future including the upcoming hi res dvd format/s.
Dvi was/is just a temporary connection...and HDMI does 10-12 bit video were DVI is restricted to 8 bit.
Always choose HDMI at this point on any new purchase if the option is there imo.
If I may blow some horn, I explain a bunch of terms for exactly this purpose at www.GreatHomeTheater.com, my website - it's written for those who don't know these things.

Something to keep in mind is that the HDMI interface supports HDCP which is copy protection. Without it you might just find yourself being DOWN-RESOLUTIONED by the evil forces of copy protection into a less than optimum picture. So that's a key consideration.
Please tell me how I can use spdif RCA to my Lexicon and bypass the audio portion of HDMI?
...from what source?
I heard that what we have now is HDMI 1.1 but that a more advanced HDMI 1.3 is expected soon (higher resolution 5.1 digital audio). Can anyone shed any further light on that? For me, it's the (all too familiar) hesitancy to invest in something now that may be outdated relatively quickly.
As an addendum to my previous post, if you do a Google search for "HDMI 1.1, HDMI 1.3" there are many questions out there regarding the possible obsolesence of the current HDMI 1.1 when the 1.3 format comes out. I hope I'm not breaking any rules by pasting these, but here are some excerpt quotes from the top few Google listings:

***...When asked why, Hipps responded, "HDMI is a moving target. With the HDMI 1.3 standard probably 2 years away, any of today's HDMI devices risk obsolescence. Rather than have a $4,000 audio receiver be viewed as obsolete because it can't support HDMI 1.3, we'd prefer to offer..."***

***(5) HDMI v 1.1 is already hitting the shelves, with v 1.2 on the way, and v 1.3 in the next couple of years (v 1.3 will deliver higher res 5.1 digital audio). What will be the backward compatibility of these versions?***

***...Also as I am sure you are all aware the standards have not settled down yet 1.2 has just be ratified but they are now working on 1.3, so introducing a decoder that will be out of date very soon didn't make sense...***

I'm having difficulty finding a straight answer on this.
The actual (official) HDMI website is here: http://www.hdmi.org/
But even here I couldn't find clear answers regarding issues such as backward compatibility etc. of 1.3 with today's 1.1.

Looks as if HDMI 1.2 will handle both sa-cd and dvd-a 5.1.
For your information - Radio Shack is apparently going with Monster brand cables in the future (go figure), so they are blowing out their Rat Shack brand HDMI and DVI cables stupid cheap - like $12.99, from $120. Get 'em while they last - I picked up a bunch for friends for the future -
15-1064 - 12 ft DVI
There's a 6 ft. DVI for the same price - don't know the part number.
15-1085 - 6 ft HDMI
My cable box has a DVI output. My TV has HDMI input. Is there any rational for using a DVI --> HDMI cable, and using interconnects from set top to TV? Or am I better off simply using component cabling? (All runs under 2 meters.)