I got into science fiction through a summer reading assignment in elementary school. At my father's suggestion, I ended up reading Robert A. Heinlein's "Tunnel in the Sky", which probably wasn't appropriate for the assignment, but that's neither here nor there. What's important is that it aimed me towards the back of the bookstore and library, where they keep the good stuff.
Today, I'm going to suggest some authors and books, some of which you've heard of and read, some of which are hopefully new and intriguing to you, and all of which are in the library of my hometown, which hopefully means that they aren't too hard to find at your local libraries, or bookstores. Or, y'know, competitively priced on Amazon.
First off, the Starfist series,
by David Sherman and Dan Cragg
I'm terrible at describing things, so I'm just going to steal from TVTropes and save myself the actual work. It's essentially the Space Marine concept, as written by former Marines. Humanity has accelerated in terms of tech, and has FTL travel. The FTL works like the Pony Express, however, which means that things don't always get places instantly, or accurately, and so the Confederation of Human Worlds Marines (And Army, and Navy) were formed to prevent rebellions and galaxy-destroying wars. Y'know, the usual. It follows the 34th Fleet Infantry Strike Team (The titular StarF.I.S.T.), a group of Marines, for several very-well-written books. "Since both authors have served in the Army and Marines, the action is very realistic for sci-fi, with downtime shown as boring, tedious work that is hardly ever exciting", but usually generates strong character development in a short span.
Next, we have Hull Zero Three,
by Greg Bear
And because I would like to keep this fairly brief if at all possible, I'm going to wrap it up with an excellent comic, Kingdom Come. A DCU comic by Mark Waid, and painted (Yeah, you read that right) by Alex Ross.
I'd like to give it a full synopsis, but perhaps the best is the briefest. (Also, dig that beautiful cover)
I played Injustice after I read it. It was kinda reminiscent, but nowhere near as poignant.
I could probably write an essay about the themes and topics of this comic, but given that this is already a full blog post, I'll pass.
Good luck, and good reading.