Taking the risk of having my post deleted, I am going to propose 2 authors that I luuurvve:
David Weber and David Feintuch (and not because they both are called David!)
For anyone who enjoyed the whole Horatio Hornblower thing as kids, but also enjoy a little speculative Space opera stuff - this is for you - big time!
Weber takes the female side through Honor Harrington, and builds a phenomenal universe spanning many different systems, of which the Solar is the oldest (and obviously the progenitor of all human worlds), he builds a huge story over almost a dozen books that will leave you very tired in the morning and swearing at the damn Z2 guy for getting you addicted!
Feintuch is a little closer to our time line, humanity has just started discovering habitable planets, and his Earth has experienced a lot of the nasty stuff that people are currently warning us of (rampant overpopulation and gang warfare etc...) Feintuch follows (and explains) the life of a young Midshipman as he climbs up through the ranks, and how a rather vicious amoeba looking alien "melt the spacesuit off you and eat your brains out" civilisation is found, and the hell that ensues - prepare for more late nights...
And just because you have read this far, I give you Kim Stanley Robinson - Start with Antarctica, then go through Red, Green then Blue Mars, we might just be there in 50 years, but more importantly is how Robinson unfolds the humanity of his characters (and sometimes the in-humanity of his characters).