Reddit reviews Excession (Ldp Science Fic) (English and French Edition)

Nobody has mentioned Iain M. Banks yet, so how about

The Algebraist

Excession

Against a Dark Background

Another military sci-fi novel with several unique twists would be Vernor Vinge's:
A Fire Upon the Deep


Hard to beat Ender's Game, though. Old Man's War is really good; Armor is good but kinda depressing.

I can think of lots more, reply if you'd like more suggestions :-)