Since I am mostly recovered from the awesomeness that was Austin City Limits 2007, here are my highlights:
LCD Soundsystem If they are playing near you, see them you won't regret it.
Arcade Fire If you happen to be one of the dates remaining where they are playing with LCD, you are very lucky. It is up there with the most amazing concert bills I can imagine.
Bob Dylan Really worth seeing beyond the fact that he is Bob Dylan (reason enough I'm aware) He is very good live. Instead of playing the songs exactly as they were they are dramatically reworked. His current version of Tangled Up In Blue might be better than the original.
And (I'm bitter about this) he has been touring with Jack White lately and playing songs he has never played live. Why weren't you in Austin Jack? The Stripes were supposed to play there anyway.
The White Stripes - Outlaw Blues This is one of the songs Bob hasn't done live that he has done with Jack. Also one of my favorites.
Apparently the White Stripes have cancelled the remainder of their US dates due to Meg White "suffering from acute anxiety and is unable to travel at this time."
http://www.eonline.com/news/article/index.jsp?uuid=8e772a9d-6348-4e63-8514-2cb8da122566