There are some great suggestions here - I'm also adding to my reading list!
I almost exclusively read sci-fi, and my favourite author is Peter F. Hamilton. He has written some mind-bendingly good space opera, much of it spanning multiple novels.
His best work IMHO is a one-shot, standalone novel called Fallen Dragon. It's got rampant uber-captialism, space marines, geurilla warfare on colony worlds, and aliens. And a very satisfying conclusion that I didn't see coming.