"Gladiator" (2000): a highly fictionalized account of the reign of Commodus, the son of Marcus Aurelius, and how one gladiator (Russel Crowe) attempted to stand against Commodus to preserve the legacy of the Roman Republic.
"Spartacus" (1960): detailing the revolt of the slave Spartacus during the late days of the First Triumvirate.
"Rome," on HBO (2005-2007): following the lives of two soldiers (Titus Pullo and Lucius Vorenus) from the rise of Julius Caesar through the death of Marc Antony and the ascendancy of Augustus Caesar, notable for its (fair) historical accuracy, and adult themes.
Robert Harris, Imperium: a tale of the life of Cicero.
Robert Graves, I, Claudius: a tale of deception, trickery, and violence in the Julio-Claudian Era, notable for its relative accuracy and its brutal treatment of the character of Livia.