Peter Dinklage rocks in the show.
Books 4 & 5 definitely drag a bit, as it was supposed to be 1 story, but Martin apparently had more to say. So the story ended up being a bit awkwardly split in two, as some major characters don't really appear in a lot of book 4. But with the pacing of the HBO show, a lot of that can be cleaned up. Although book 5 ended with enough to hopefully keep me intrigued until book 6. Unless Martin takes another 6 !@#$ing years to write a book. I hope it only took 6 years because he spent so much time getting the TV show underway...
I think there are supposed to be 7 books total (but it used to be 6 at one point, so 7 could turn into 10 or 12...)
At the pace of the show I think they are trying to do a book a season. At least that's what they did with season 1 and book 1.
Good book series, and good TV show (at least season 1, since I'm too cheap to pay for HBO).
Oh, and Peter Dinklage rocks. Perfect guy for an awesome role.