Identifying what type of Xbox 360 you have By The power connector on the console.
<img src="http://i38.tinypic.com/zo9c1u.jpg" border="0" alt="Image and video hosting by TinyPic">
This is just a simple picture showing the different variations of xbox's through their power connectors.

But Lots of people think that xenons,falcons,jaspers,zephyrs and so on are just Jtags no they are the chip-sets inside of your xbox otherwise known as the MotherBoard.

Every Xbox 360 to date is identifiable by multiple factor like year you purchased the xbox(1st gen,2nd gen so on)and If it is HDMI or non HDMI and By looking at the power connector on your console but now each type of xbox and their specs.

Xenon MotherBoard-First Generation xbox 360 to launch in 2005 which is non-HDMI and is prone to Red Ring of Death as some of you may now.Although Its prone to Red Ring Of Death it give you the option of using both type 1 and type 2 KV's

Zephyr MotherBoard-Released in early 2006 Almost Identical to the Xenon MB but is in an HDMI format although still prone to Red Ring of Death

Opus MotherBoard-The opus Is second Generation xbox 360 released in Early 2007 With a new chipset in hopes to completly rid of Red Ring of Death Although it is not completely incapable of getting Red Ring Of Death it is less prone.

Falcon MotherBoard-The Falcon Was Released In late 2007 and Its chipset is similar to that of the Opus but its Hdmi Capable.Some Say This is the Best and most reliable when Jtagged but is still Capable of getting Red Ring of Death.

And Finally

Jasper MotherBoard-The Latest Chipset To be released in mid 2008 and the 3rd Generation xbox 360 this xbox Is less prone to Red Ring Of Death Than any other Chipset to date and is fully capable of HDMI settings.To find a Jasper in a jtag format is rare and if you can find one they dont come cheap.

Ok Now a look at what each MotherBoard Looks Like
Xenon:


<img src="http://i33.tinypic.com/2ld92pz.jpg" border="0" alt="Image and video hosting by TinyPic">

Zephyr:


<img src="http://i37.tinypic.com/2nrd4wm.jpg" border="0" alt="Image and video hosting by TinyPic">

Opus:


<img src="http://i37.tinypic.com/oaykqs.jpg" border="0" alt="Image and video hosting by TinyPic">

Falcon:


<img src="http://i33.tinypic.com/2uq19bt.jpg" border="0" alt="Image and video hosting by TinyPic">

Jasper:


<img src="http://i36.tinypic.com/6i4pcy.jpg" border="0" alt="Image and video hosting by TinyPic">

Ok I hoped I helped You Guys and cleared up some peoples questions!