It all depends what you're interested in. Why not browse the offerings in your local book store or library?
Do you want fiction? If so, adventure? mystery? romance?
Non-fiction? If so, politics? history? science?
I don't think the specific books make any difference. The same grammatical structures will appear in any book you choose. And if you choose, over time, a good variety, you'll get exposure to many different spheres of vocabulary.
You could even just browse the Internet, especially forums, if you want to get the flavor of informal conversation on a variety of topics. You'll encounter some bad grammar, and some slang, but it will all be, on the average, fairly representative and authentic English.
CJ