i read all the books as they were published and the show is truly great, but i dont know how you could watch it without reading the novels. i call the show "fast forward of thrones" because a 5 minute scene encompasses an hour of detail in the books. strange to see things in the shows background, all done in exquisite detail, never explained in the show.
i like to listen to audiobooks while i work, and the ones for this series are truly amazing. roy dotrice got a guiness record for his work on the audiobook. if you are into the show, but dont have time to read em all...or if you have read them and want to get a "close read" i recommend it.
I've got the SOIAF box set on pre-order at Amazon.
I generally tend to view TV/Film versions of popular books as totally separate stories-usually quite reasonable as things get changed so much. Seeing a film or TV show first doesn't spoil it for me as there are always lots of details/sub-plots missing from the TV/Film.
I hated the Alex Cross(James Patterson) films(Kiss the Girls+Along came a spider) with Morgan Freeman--totally the wrong man to be Dr/Detective Cross--Delroy Lindo or the chief from "The Wire" -the one who had the tolerance zone for drug dealing--much better choices and fitting the description of this very large man.