There are some great recommendations on here. But one of the problems with no having read much is you often don't know what you like, as you've said, or you read stuff which you might have appreciated more after having read some other stuff first - but I suppose this will always be the case. Anyway, I also got 'into reading' quite late, and I found these useful as they allowed me to know what I like without reading shit loads of 'heavy' books which I may not have enjoyed. As such, I rarely pick up a book and dislike it - very good for 'catching up' on lost reading time!
A Short History of Nearly Everything - Bill Bryson: History of the sciences, with major theories or ways of thinking explained. Excellent for the non-scientist, or someone who just wants a superficial understanding of the major sciences for possible avenues of interest.
Sophie's World - Jostein Gaardner: Similar to the above, but for philosophy. Explains each what each branch of philosophy is about, but again, only superficially. Good starting point.
I'm sure similar books to these two exist for 'beginners' about different topics. The Oxford University Press has a good series called "A Very Short Introduction to..." which covers a lot of ground, but are a fair bit less accessible than these. Here's some other stuff which I enjoyed:
Fabric of the Cosmos - Brian Greene: It's a history and explanation of physics starting with Newton and going through to string theory and where we are today. It's much more enjoyable than Hawking's Brief History of Time, with better analogies, etc., but it covers similar ground. Good follow up to Bill Bryson if you're interested in this branch of science.
The Ragged Trousered Philanthropists - Robert Tressell: Mentioned earlier, but worthy of another recommendation. Working class tale with a lesson on socialism thrown in. Quite funny, too, in parts!
Sirens of Titan - Kurt Vonnegut: As mentioned earlier,
Slaughterhouse Five is an excellent book, and I thought I'd always recommend that if talking about Vonnegut, but
Sirens is even better, I reckon. Manages to be funny, poignant, tragic and absurd; and is amazingly easy to read. This and Slaughterhouse Five are well worth checking out.
In Dubious Battle - John Steinbeck: I read
Grapes of Wrath, mentioned earlier, first, and loved it. But this is my favourite by Steinbeck. It's about two Communists sent in to organise strikes in the fruit farms in California during the Great Depression, and the tactics used against the migrant workers by the bosses. Fantastic!
Of Ape and Essence - Aldous huxley: A post-apocalyptic novel which shows America, I think, after the Third World War (an all-out nuclear war) and the collective suicide that is industrial warfare.
Hopefully there's something there for you
