The frustrating thing with starting to learn NT Greek is that it takes a while to be able to do anything with it. Once you have completed a basic grammar (I recommend Mounces's Basics of Biblical Greek in the same series), you should buy yourself this as a reward. At last you can put your hard work to good use!
Main reasons to choose this grammar above any other:
1) It is incredible readable considering how in depth it is. Never has a book so scholarly, been so accesible. 2) It is thoroughly evangelical, yet honest - not afraid to challenge traditional evangelical interpretations. 3) It shows the huge difference that knowing NT Greek makes to understanding & teaching the Bible, without ever over-stating the case - it clearly shows the limitations of Greek grammar too. 4) It is so practical! Nobody who teaches the Bible regularly will fail to read more than a few pages without seeing how the grammatical point they are studying will affect their teaching. The emphasis on the exegetical applicability of the grammar is second to none.
No one who teaches the NT should be without a copy - even if you don't read Greek you can glean much and you will be reminded of why you should.
(Final note: this book is ideal for reference purposes, but there is an abridgement of this book (Basics of NT Greek Syntax?) which would perhaps be better for the intermediate student working through from cover to cover)