Where was Tywin? I don't recall seeing him...
They've been pretty true to the book so far. The third episode had a few conversations that didn't happen in the book (Cersei and Joffrey, Robert, Barriston and Jaime), but needed to be done to fill in viewers who didn't know the back story. Now that most of the key characters (for now) have been introduced, I wouldn't mind them starting to do some episodes that focus on just one or two locales (say, all in King's Landing, or split between the Wall and across the Narrow Sea) to keep the stories from jumping around so much. It might be helpful to viewers who haven't read the book.
I love the casting for the series; the casting is pretty much spot-on for everyone, Tyrion and Arya especially. The only one who bugs me at the moment is Robb Stark - he just seems a little wooden. Hopefully that changes when he's forced to grow up.
And I saw posted elsewhere that book 2/season 2 already has the green light. Viewership in North America isn't as high as it could be, but they're making a lot of money selling the show in other countries.