all first person shooters are war games , it what shooting is . it's war
good story modes in them would be killzone 2 or cod 4
others with a good story mode are mgs 4 , infamous and gtaIV
all can be beat in a week or less but gtaIV has enough extras you can do to keep busy a while and infamous changes depending if you're good or evil so you play it twice
as for fps , nobody buys them for the campaign mode , they buy them for online play