I'm fond of the
Mageworlds series by Debra Doyle and James Macdonald, which is essentially Star Wars with the serial numbers filed off. That said, the books are a lot of fun even if they're not what you would call wildly original. There are three books in the main trilogy -
The Price of the Stars,
Starpilot's Grave, and
By Honor Betray'd. They're all out of print, but you can pick up used copies on Amazon for a penny each, plus shipping. If you like those there are some prequel novels and a "next generation" novel waiting for you.
Meanwhile, for a wonderful military SF series with a terrific protagonist, I cannot recommend
Lois Bujold's Vorkosigan Saga highly enough. I generally recommend starting with the
Young Miles omnibus, which introduces you to the manic, brilliant Miles Vorkosigan who manages to get up to all sorts of trouble in ways that tend to involve the perils of being a space marine, the politics of wormhole gates, and the impact of biotechnology. I guarantee you will enjoy reading the many ways the man leaves all hell breaking loose in his wake. If you enjoy that volume, either move on to
Miles Errant or backtrack to
Cordelia's Honor for two volumes involving Miles' parents.
FnordChan