If you're into urban, modern-day fantasy, read Neverwhere by Neil Gaiman. He's hardly an obscure author or anything, but it is my favorite book of his and may be one of my favorite fiction books period. He creates a world based on abandoned bits of the London underground and other places that only the ignored/invisible dredges of society would go. Richard Mayhew helps an injured girl, who's part of that world, and in doing so he becomes a part of it, so they both spend much of the book trying to evade mythological murderers, while Richard just tries to get back to his old life. Fun fact! It was a BBC miniseries first, and Gaiman wrote a book based on it later.
If you're into regular fantasy, but think it has a tendency to be stuffy and/or full of ridiculous tropes, read... pretty much anything in the Terry Pratchett's discworld series. It's fantasy satire and pretty funny, but he creates engaging characters and storylines in the process. You can pretty much pick up any book and figure out what's going on, but starting with The Colour of Magic, Equal Rites, Mort, or Guards Guards! is a safe bet as each one introduces a distinct set of characters. (There are a ton of them.)
For nonfiction, I found Proofiness by Charles Seife pretty interesting. It's about ways people can use numbers that may be true, and use them in every dishonest way imaginable.
If you're interested in history, Assassination Vacation by Sarah Vowell is a good read (as are her other books). I find a lot of history books hard to get through because the tone is, well, boring, but her style of writing is really accessible.
It's a comic, but I'd highly recommend Maus by Art Spiegelman if you're interested in personal stories about Jewish life in Germany during WWII and you are also interested in being really depressed for a while.
Also, if you like supernatural/werewolfy fiction but hate all the YA "supernatural romance" shlock that's everywhere these days, Bitten by Kelley Armstrong is good. The only female werewolf has to go back to her estranged pack (including the guy who bit her) and track down a pack of murderers. (It does get a bit racy and a bit, well, murder-y. Fair warning.) The author has written more in the series, but I haven't read any of it yet.