[craiglester]

You could do worse than the Honor Harrington books by David Weber, theres i think like 10 or 11 of them.. should be able to pick them up pretty cheap second hand too..

 

[Chrispy]

I just finished "Shadow of the Giant." Most recent of the Bean series. There's supposed to be a final book reconnecting both storylines

 

[Superpredator]

Some novels you might enjoy:

Samuel R. Delany - Nova
Samuel R. Delany - Babel-17

Ursula K. Le Guin - The Left Hand of Darkness (most realistic setting and tone of any science fiction novel I have ever read)

Vernor Vinge - A Fire Upon the Deep