Season 1's adaption was almost page by page. I loved the Khal Drogo fight scene they put in the show though, I think the viewers really did need to see what a badass he actually was.
Season 2, I've been mixed on... Didn't like Daenerys' boring story in ACOK, but haven't been a fan of the stuff they've made up for her this season either. I usually find myself waiting for her scenes to end just so we can get to the important stuff. Looking forward to the House of the Undying though.
I don't think they've done Jon's story much justice this season either, it was probably my second favourite POV after Arya's, but it has dragged out a bit. Somehow I don't think book Jon would have been stupid enough to chase Ygritte for miles in Wildling territory either. Halfhand was about ten times better in the books aswell.
But again, I've liked a few things they've added. Big fan of Robb, the more of him in the show the better, even if they have changed some big points on that whole Jeyne/Talisa front. That scene with The Hound and Bronn in Blackwater was excellent. Renly was far more interesting in his short stint on the show than I found him in the books, same with Magaery. And Stannis... I really couldn't make my mind up on him in the books, but I love show Stannis, he is one of my favourite characters.