a fistful of dollars (1964)

aka Per un pugno di dollari.
An anonymous man (Clint Eastwood) rides into a New Mexican town on a mule, and decides to stay when he finds out that it is torn in two by a gang war between the Baxter's and the Rojo's. He schemes to make money from both sides by playing them off against each other, but his plans are complicated when he gets involved with Marisol (Marianne Koch) and decides to reunite her with her husband and child, despite one of the Rojo's taking her for himself.
From the opening titles you know this is going to be a classic and served to popularise the spaghetti western genre. From the music, the script, and the cinematography, all add to make a classic western. And even though it is a thinly disguised remake of Yojimbo (1961), it takes the basics of that film and makes it all its own.

the baader-meinhof complex (2008)

aka Der Baader Meinhof Komplex.

The film charts, in a pseudo-documentary way, ten years in the life of the Red Army Faction, or as they were more commonly known the Baader-Meinhof gang. From their beginings in the radical 60's, through to the bloody events of the 70's, the bank robberies, kidnappings and plane hijakings.
Not really a b-movie, but a great bit of film making. Due to the amount of events and the long time span the film rockets along at a breakneck pace, leaving little room for character development; some people are omitted or combined. But for all that it gives a great overview of the era and the events. It tries to stay neutral, preferring the events to speak for themselves, rather than allowing political polemics to overtake the film. It also does not shy away from the very real brutality of the gangs actions, you feel every bullet and bomb.