Banks often used conflict as a plot device, but (from memory) only Consider Phlebas and Use of Weapons include much actual warfare. You could try The Player of

Banks often used conflict as a plot device, but (from memory) only Consider Phlebas and Use of Weapons include much actual warfare. You could try The Player of Games (my personal favourite) or The Hydrogen Sonata, which has a fairly peaceful storyline. And The State of the Art - a collection of short SF stories - is very good too.