Definitely this one:
http://www.amazon.com/Novum-Testamentum-Graece-Eberhard-Nestle/dp/3438051001
(Not that expensive, and not the same as in TD's link which is the so-called Editio critica maior -- the price in TD's link being for only one small part of the NT; you don't need that I think).
The exact same Greek edition is also available in the Greek New Testament of the United Bible Societies -- only the critical apparatus differs; there are less variants but easier to understand. (Mind that the 27th edition of Nestle-Aland corresponds to the fourth of GNT.)
I think you were refering to the word-to-word translation in the KIT (that under the Greek text, not the NWT in the margin) which I agree is not that bad. However if you want to learn NT Greek you have to avoid interlinears (although you can read one of them additionally for easy practice).