I bought GITS: SAC 1st Gig for my Birthday in March last year, following buying the first Ghost in the Shell movie (didn't watch the second as I didn't like the idea of the Major not being there). Like one of the other reviewers said this series is complicated, and relies on you listening and remembering what had happened in previous episodes.
I think there are about 26 episodes in the season, and all but one or two are just great. The story gradually unravels and you are taken through a sci-fi world in between reality and the 'internet world'.
You'll find yourself being pulled into a story that can confuse you at times, but also intice you and makes you want to find out why events have happened, and other things that can't be said without being classed as spoilers.
Most of the 1st Gig (season) revolves around the 'Laughing Man' incident (these are 'Complex' episodes, whilst the rest are 'Stand Alone'/ single episodes), a case that is incredibly complicated as it seems to be linked to everyday events and occurences - I won't say any more about this as it really is just to good and I don't want to spoil it.
GITS revolves around the daily occurences of Section 9, a Japanese secret police force that works both for and behind the Government. Motoka Kusanagi (aka the Major) is a female cyborg that is usually involved in the action events in each episode (but not always), whilst the second main characters, Togusa and Batou, are often involved in the more unorthadox events. The cyborgs are not, however, actual robots - most are humans that have been fitted with machine parts in order to improve their performance - this idea is explained as the plot expands.
I found Stand Alone Complex to be an amazing idea, and it went into much more action and depth than the slightly more bizarre movie. For a complete boxset of an amazing series, buy this from Amazon. £30 - what have you got to lose? If you like anime or the GITS movies then you will love this.
I loved this so much that I didn't want it to end; but now, with the 2nd Gig being released in a box set, roll on February 2007!