A preacher with college and seminary training can hardly keep his self-respect if he does not have upon his study table a Greek Testament, a Greek lexicon, a Greek grammar, and several modern commentaries on the book that he is studying. He will have many other books, of course, but these are prime necessities if he plans to do serious work upon a page in the New Testament before he preaches upon it. Only thus can he be sure of his ground. Only thus can he be relatively as original as he ought to be. The contact of his mind with the Greek Testament is a fresh experience of first importance. The mind of the Spirit literally opens to his mind in a new and wonderful fashion.
-- A.T. Robertson, taken from The Minister and His Greek New Testament
If you don't have a copy of Robertson's little classic, buy one! If you do, get it out and re-read Chapter 9, "John Brown of Haddington, Or Learning Greek without a Teacher." That chapter alone ought to re-kindle the fires of learning and drive you to your Greek New Testament!
And if you are looking for a helpful Greek New Testament, I would recommend the UBS Greek New Testament: A Reader's Edition. It contains the vocabulary for all words occuring 30 times or less in the New Testament at the bottom of each page, a dictionary in the back for all words occuring 30 times or more in the New Testament, grammatical help for difficult verbs, and a much better font and layout than Zondervan's Reader's Greek New Testament. You can purchase the UBS version here.
