I'm a big fan of the comic book, and it didn't bother me that it deviated from the books. Mostly because the creator, Robert Kirkman, was on board with the changes. It seems to be headed in the same direction, it just finds other ways to get there sometimes, which is fine by me, as long as it respects the source material. Obviously some things will have to be different, like the comic isn't in real time, so after all these years, Carl is only what, a year and half older or so? The kid that plays Carl on the show will of course grow at a normal rate, so his storyline will have to be altered as the show goes on.
I also really liked some of the characters created for the show, like the Reedus brothers, they brought a lot of conflict to it. I thought they got Glenn just right, and I like that they seem to be keeping Shane around longer. Kirkman said he probably would have done that too if he had known the book was going to be a hit, but he didn't know how long he would have to tell his story, so he got rid of Shane early on. There are major points of the story I want to see on the show, but I don't want it to be a carbon copy.
I wish Darabont wasn't leaving, he's a great storyteller in his own right, and he had such passion for the story. I imagine it was hard for him to work within the budget limitations of tv is my guess, but his number 2 is taking over, and Kirkman is still involved, and he has said he will be writing more episodes this season, so it's in good hands.