There is an interesting discussion over at the Westeros forums regarding where to end the pilot episode. Obviously this discussion is all spoilers, so click through only if you’ve read the first 200 pages of the first book.
The general train of thought is to end the pilot at the “things I do for love” scene. Bran sees Jaime and Cersei in the tower, Jaime throws him out the window and we fade to black. Hopefully the audience is hooked at that point. A poster at the Westeros forums, The Anti-Targ, has a slightly different idea though. Instead of ending it there, extend it a few more scenes and conclude it at the assassination attempt. He contends that not only does it add another level of excitement but it is a good wrapping up point for the episode.
Winter is Coming: I rather like this idea. It makes for a more complete episode. We’ve seen Eddard make the decision to become Hand and leave for King’s Landing, we’ve seen Jon and Tyrion leave for the Wall, everything seems to be settling down at Winterfell. It also adds another layer of mystery to the whole thing. Yeah, Bran getting thrown from a window is pretty shocking, but we know who did it and we know why. Ending on the assassination attempt is a little more mysterious as we don’t know exactly who ordered the attempt (although one could make a guess). They could also leave it vague as to whether or not Catelyn and Bran survived the attempt.
Another benefit to this idea is it adds a little more action into the pilot episode. Throughout most of the episode not a lot happens. It is mostly establishing the world, establishing the characters, etc. Viewers might get bored after a while. Ending it at the assassination attempt adds another little twist and turn and some more action to the pilot to hook viewers even more.
In the end, the decision has already been made by Benioff and Weiss where to end the pilot. The script has already been written. While they may make minor changes, they most likely won’t be changing the ending point. But it is fun to speculate!