"...is subject more to rules of fragrance than of grammar."

Because I'm a presumptuous bastard and in an audacious enough mood to put this list together, here be recommendations of must-read Nihongo-related books for students in the same boat as me:

Making Sense of Japanese (Jay Rubin) 

Hilarious! I would suggest reading this at home unless you're the kind of masochist who derives pleasure from the embarrassment of being stared at while guffawing in public (alright, what's wrong with you?). Mr. Rubin expounds in his own easy fashion on niggling questions that tend to loiter at the back of students' minds, questions they may be too shy to ask their sensei because the answers seem like they should be glaringly obvious and they feel moronic for not intuiting them in the first place or because they have suspicions of walking away even more confused when they do get further explanations. The book will make the most sense by the time you've tackled causatives and all the complications thereof, but I've read it when I was still mucking about in conditionals so I'm guessing it can be enjoyed by students of all levels since the writing style is quite accessible even for beginners.

どんな時どう使う日本語表現文型辞典 (友松悦子, 和栗雅子, 宮本淳) 

If you have to get just ONE book on Japanese grammar, this would be it. It lists the grammar patterns, each with its own example sentences and clarifications on when and how to use it. The book's fairly exhaustive and includes English, Korean, and Chinese translations and very essential if you're currently studying the language by yourself and would like to add some semblance of structure to your 文法 reviews.

Kanji & Kana (Wolfgang Hadamitzky & Mark Spahn)

I'm sure there are better and more comprehensive Kanji books out there but this is the first one I bought and you know what they say about your first. Anyway, it contains a list of the 2,000 常用漢字 (more accurately 1,945, but let's not nitpick on accuracy here), with over 4,000 readings, approximately 9,000 compounds, and a basic vocabulary of about 11,000 words. Oh, and each Kanji has nifty numbering at the beginning of each stroke so you can draw them in the correct order all by your lovely self. Isn't that nice? I think these are the most you can ask of your Kanji book unless you want it to sing you an enka 'til you drift off to the Floating World riding atop the Hokusai wave in which case, you're on the wrong homepage, bub.

501 Japanese Verbs (Roland A. Lange & Nobuo Akiyama)

If you're like me and you want to tear out your hair in frustration because goshdarnit how many verb conjugations can one reasonably remember without bleeding out by the ears at the end of the lecture, this book is for you. Each page contains a verb and all its conjugations charted out according to informal/formal usage and in the affirmative/negative form. Undeniably useful, this.

Right, ending the list right here because for some inexplicable reason, I'm getting rather annoyed the longer I ponder on what else to add to it. And also, I want to talk about other things. Like, are you taking a class in Japanese? I've often been asked why I needed to take a class when I can just read all these books. But then, if I have buuurning questions, who should I ask? Consulting an "expert" online is all well and good, but it won't be too long before he starts hurling Apollo strawberry chocolate candies at you by the fistfuls (futilely because he's on the other side of the computer screen) with Cheetos-stained fingers because you keep interrupting his The Melancholy of Haruhi Suzumiya marathon.