Would someone tell me what, if any, are the major changes from the books UP TO SUNDAY'S EPISODE? I'm aware that some of the battle scenes have been cut because of budget, but from the sound of things, this show might get in a much different direction than the books, which would make me sad because Martin deserves to have his vision translated to the screen relatively intact. I hope HBO doesn't pull a True Blood or Walking Dead with this.
There aren't any significant changes that have yet affected the storyline ala the Dexter books or The Walking Dead. Mostly so far it's been certain plotlines moved up to give some characters more screentime, certain minor characters being merged or excluded from the show, and tweaked plot points within arcs that still lead to the same outcome.
For instance, the leadership of Qarth is slightly different but with the same major characters (X.X.D., Pyat Pree). The "someone took my dragons!!!" plotline we just saw didn't happen in the books AFAIK. Jon Snow getting separated from the scout team with Ygritte didn't happen in the books, but they do share a ton of time together in the story so it's not that big of a deal IMO.
Other plot changes include Littlefinger travelling to Storm's End to meet with Renly & Cat, and him travelling to Harrenhal to meet with Tywin. On that note, the book Tywin never stayed in Harrenhal for the period he is right now.
That said, there is a little trepidation among bookreaders right now that the currently minor changes may somehow cause a ripple effect making the changes major. So far I'm not seeing it, nor am I worried about it.