The Boomer Investigators of NCIS and CSI

McCallum, 77, was previously best known for his role as the Russian spy Illya Kuryakin in the iconic 60s TV series The Man from U.N.C.L.E. These days, hes forensic psychologist Dr. Donald Ducky Mallard, who served with British troops in Afghanistan. Mallard has a dry and occasionally spooky sense of humor; he calls bodies in the morgue guests and talks to them.

Helgenberger, 52, first became a familiar TV presesnce playing a prostitute on the 1980s Vietnam drama China Beach. In CSI, the original series in the CSI franchise, shes Catherine Willows, supervisor of the aptly-nicknamed graveyard shift of the Las Vegas Police Department. And her gruesome specialty is blood spatter analysis. But she loves her job, telling a coworker that after she solved her first crime, she felt like King Kong on cocaine.

Yet another strong, self-contained investigator, Lt. Horatio Caine, played by Caruso, has a checkered past when he arrives from New York to do police work in Miami (He killed a man, and was stabbed himself.) As a police officer, Caine is licensed to carry a gun, unlike the other investigators, and favors Beretta and Sig-Sauer semi-automatic pistols. Caruso, 55, first made a name for himself playing a similar character, Detective John Kelly, in the series NYPD Blue.

Sinise, 55, who was nominated for an Oscar for his role as a psychically and physically damaged Vietnam vet in Forrest Gump, plays a similarly tortured character in CSI: New York. His character, Mac Taylor, is an ex-Marine who was injured in the 1983 bombing of a USMC barracks in Beirut. His just-the-facts approach doesnt allow for any intuition in solving a case. Instead, Taylor, whos familiar with almost every kind of weapon in existence, prefers to focus on how the victim was killed.