Season One of Terminator: The Sarah Connor Chronicles came out on 8/19/08 and comes with the usual set of extras: gag reel, deleted scenes, episode commentary, and featurette. (featurette/commentary spoilers)
 
DVD Extras include: 

Disk 1: Gag Reel
A yeoman effort made up mostly of flubbed lines and mal-propisms. The highlights being any time one of the Terminators did something spectacularly not Terminatorish, Dust-devil garbed Cromartie picking up the biotech scientist by his crotch, and Lena Headley doing a little dance when surrounded by nuclear scientist with guns.

 
Deleted scenes:
Disk 1: The Pilot, the Turk,
Disk 2: Dungeons and Dragons,
Disk 3: Demon Hand, Extended Demon Hand 

Deleted scenes were a mix of understandable cuts and interesting insights. The highlight for me really being the extended Sarah Connor insane asylum interview in Demon Hand. It put an entirely new complexion on the scene. It gave Sarah a classically Luddite background and provided a horrifying mental image of lost childhood as a broken backed bicycle, which is, of course, a kind of machine. Also given Sarah’s role as mother, it reminded the viewer that Sarah was once a child.

3 featurettes
~Creating the Chronicles: Re-Boot
~Creating the Chronicles: The future war
~Creating the Chronicles: the Demon Hand

The featurettes provide good value with behind the scenes explanations of the thought processes behind various arcs. 

“Creating the Chronicles: Re-Boot”  was my favorite with a solid view of everything that goes into assembling the creative vision behind Sarah Connor. There were interviews with not only the Producers and stars, but with the stunt and visual effects people who craft the look of the series.

“Creating the Chronicles: The future war” went into a fair amount of detail on the challenges of creating the future scenes for Dungeons and Dragons. Originally it was going to be very WWII and Great Escape. Happily, they went in a more psychological direction. A special gold geek star goes to James Lima, their visual effects coordinator, for his explanation for how Chrono-transportation works in T:tSCC. 

“Creating the Chronicles: the Demon Hand” had a fair amount of background discussion of the thinking behind the writing and visual choices in “Demon Hand”. This featurrette had a beautiful juxtaposition of image and description. They showed the image of Ellison standing over the good doctor in the rain and surrounded by rainbows. Then the producers discussed how the return of Sarah served as a spiritual reawakening for Ellison. He had been going through the motions, but now he has remembered his desire to succeed. As I looked again at the rainbows and heard their explanation, it seemed to me that Sarah served in this episode as Sophia, the wisdom of God, for Ellison. This was only reinforced when the writers explained that Sarah saved Ellison from the fire because she values life. She's trying to not only teach John how to survive, but how to survive well. This fits in very well with the sort strategic thinking described in Sir Basil Liddell-Hart’s book “On Strategy,” which articulates that when you fight a war, you are creating the peace that will follows. Given the number of fictional narratives which espouse a Clauswitz-ian, “Blood is the price of victory,” approach, it was interesting to hear another sort of perspective. I've be very curious to see how that unfolds as the war and series go on.

Episode Commentary
~Disk 1: Pilot: Josh Friedman, James Middleton, David Nutter, Summer Glau
~Disk 1: Turk: Josh Friedman, John Wirth, Lena Headley, Thomas Dekker
~Disk 3 What he Beheld: Josh Friedman, Ian Goldberg, Summer Glau, Brian Austin Green

Overall, the commentaries did a good job of balancing insights with humor. This was achieved primarily by having Josh Friedman act as moderator. When things got slow, he'd ask leading questions about thought processes or throw in his own insights. They managed to avoid the problem where commentators start watching the show and forget to comment, or focus solely on one type of insight. The mix of actors and writers/directors provided a little bit of everything. 

“The Pilot” commentary had a lot of technical details about filming in New Mexico. Since they discussed many of the things mentioned in the featurettes, I'd say it's a good idea to watch the first featurettes before watching the commentary. 

The “Turk” commentary was really well balanced with the writers and actors playing off each other into humor and background insights. 

In “What He Beheld”, Brian Austin Green made an interesting point about Derek's birthday gift to John. On one hand, he's doing a very nice thing, but the result is that it somewhat manipulatively benefits Derek by drawing John closer to him. This is further emphasized by John keeping the "gift" a secret from his mother later. What is somewhat boggling about re-watching the scene is that while they were filming that highly emotional scene in the park, there were FBI agents being catapulted into an inflated pool about twelve feet away.
 
Disk 2: Story Board Animation
This was a mildly interesting feature for budding tv writers and producers. T:tSCC spends extensive time story boarding because they are such an action intensive show.  

Disk 2:Cast Auditions: Lena Headley, Thomas Dekker, Richard T. Jones
Disk2: Summer Glau Dance Practice

An interesting set of auditions for understanding how the actors got their roles. It was particularly interesting because Jones’ audition was for Ellison in the ‘90s, a man who was going places, rather someone who has been stuck. Summer Glau’s dance practice was Summer Glau doing a dance practice, which I'm sure some will find appealing.


All in all, the DVD set is a good value and should help fans gear up for the new season, and introduce new fans to what they missed.