More geared towards conflict and war. Any books on the Troubles for example would be nice.
I just finished reading the Iggulden books (Both on Julius Caesar and Genghis Khan), brilliant. Anything in that type of vein.
I haven't anything in regard to the Troubles but as for Rome and in the area of war and conflict as opposed to detective based as some of them are...
Look up a book called Eagle in the Snow by Wallace Breem
It focuses particularly on Roman Britain in the latter half of the 4th century and then Gaul, Belgica and Germania in the early 5the century right up to when the Rhine froze [and we all know what happened after that].
Also consider the series by Simon Scarrow. That is set during the reign of Claudius.
There are others i would recommend but they are not so predominantly set around a war setting.
I could offer up a suggestion or two for the dark ages, medieval period, and parts of the 17th, 18th and 19th centuries if you're interested.
EDIT: If Ancient Greece takes your fancy, Steven Pressfield is a rare talent in his quality in that time period. Start there.