Sometimes in Hollywood, sparks fly not just between costars, but between actors and their directors too. These pairings have a way of elevating what might just be mediocre material into pure genius. As this week's Robin Hood marks the fifth time Ridley Scott and Russell Crowe have worked together, we look back at some of the greatest director/actor duos of all time.

-- By Stacie Hougland

John Wayne and John Ford

These two tough-talkers embarked on a quarter-decade partnership that resulted in 15 films, including what's known as the best western ever made: The Searchers in 1956, as well as Stagecoach, The Man Who Shot Liberty Valance, Hondo and, um...Donovan's Reef.

Martin Scorsese and Robert De Niro

Director Brian DePalma introduced Scorsese to De Niro in the '70s; over the next few decades they went on to make some of Hollywood's most influential and groundbreaking movies together: Mean Streets, Taxi Driver, Raging Bull (the movie which De Niro helped Scorsese kick a cocaine addiction to make), and Goodfellas among them.

Martin Scorsese and Leonardo DiCaprio

In his later years, Scorsese seems to have adopted Leo as his young favorite, casting him in such movies as The Departed and Gangs of New York. Next up for both: The biopic Sinatra.

Humphrey Bogart and John Huston

Who better to direct the hard-drinking, always-smoking Bogie, but his always-smoking drinking buddy John Huston? The director guided Bogie as hardboiled detective Sam Spade in The Maltese Falcon and as a gold-hunting prospector in The Treasure of the Sierra Madre. They showed their lighter side with Katharine Hepburn and African Queen in 1951.

Woody Allen and Diane Keaton

Allen cast Keaton in a 1970 Broadway play, and they started seeing each other during that time. Their teaming brought us the comedy standard-setting (and Oscar-winning) Annie Hall, their most noteworthy film together. They have not worked together since Keaton replaced Mia Farrow on Manhattan Murder Mystery in 1993.

Woody Allen and Mia Farrow

Farrow and Allen became romantically linked in 1980, and from then into the '90s she starred in most of his best films of that period, including Broadway Danny Rose, The Purple Rose of Cairo and Hannah and Her Sisters. Unfortunately this fruitful relationship ended with onevery public custody battle after Woody and adopted daughter Soon-Yi had an affair.

Alfred Hitchcock and Jimmy Stewart

The relationship between these two iconic Hollywood figures spanned less than a decade, but resulted in four of Hitchcock's most famous and notable films, including Rear Window and Vertigo.

Katharine Hepburn and George Cukor

Legendary director Cukor worked with just about every leading lady of the time, but found enormous success with good friend Hepburn in such films as Little Women, The Philadelphia Story. He also directed the famous pairing of Hepburn and Spencer Tracy in a number of films including Adam's Rib.

Tim Burton and Johnny Depp

This eccentric duo is probably best known for Edward Scissorhands and the recent Alice in Wonderland. Why do they work so well? Burton's bizarre sensibilities make the most of Depp's quirky personality--and penchant for outrageous hairdos.

Steven Spielberg and Tom Hanks

Whether comedy or drama, Spielberg's deft direction has brought the best out of Tom Hanks, in films as lauded as Saving Private Ryan and as lovably goofy as The Money Pit.

Quentin Tarantino and Uma Thurman

Thurman has been quite rightfully called Tarantino's "muse," and her star quality arguably helped launch the director's star with Pulp Fiction.

John Carpenter and Kurt Russell

Russell played Snake Plissken in both Carpenter's Escape from New York and Escape from L.A. with aplomb, but it's still their work on the chilling The Thing that marks their best collaboration. Big Trouble in Little China notwithstanding.

Molly Ringwald and John Hughes

Would Hughes's "Molly trilogy" (Sixteen Candles, The Breakfast Club, Pretty in Pink) have been the same without star Molly Ringwald? A teen herself in Hughes's iconic '80s movies about love, angst and fish out of water, Ringwald brought a delicate yearning sensibility to the director's peerless writing.

Billy Wilder and Jack Lemmon

Wilder turned Lemmon into a true leading man, keeping his sometimes over-the-top acting perfectly in check. Some Like It Hot may be the flashiest role Lemmon had in a Wilder film, but his finest role was in the The Apartment.