I got a chance to watch the first episode of The Sarah Connor Chronicles this weekend. I have to say I'm impressed. They completely ignore T3 (Thank God!) and start their own timeline. The new Terminators are much more human in their actions, so they have a wider range of expression and therefore more possibilities exist for their characters. As much as I love Arnie as the T2 Terminator, you have to admit a season of his wooden robot mannerisms would have gotten old quick. Plus, Summer is easier on the eyes.
Leana Heady channels Linda Hamilton so well it's almost spooky. Her voice even has the same inflections as Hamilton's while doing the voice overs. Thomas Dekker is a fairly good John, and I would say an improvement over the previous two incarnations. (Let's face it, screechy-voiced John from T2 was the movie's most annoying aspect.) Summer Glau was the perfect choice for a female Terminator. She plays weird, emotionally distant characters very well. (Firefly, anyone?)
I'm downloading the second episode now, and crossing my fingers in hopes that they keep the quality up.