03/12/2012 02:06 pm ET Updated May 12, 2012

Ten Actors Who Should Have Been Leading Men

If you look at the many leading men who have become household names over the past 60 years, you'll recognize these names: Humphrey Bogart, Clark Gable, Rock Hudson, Kirk Douglas, Paul Newman, Michael Douglas, Tom Cruise, Brad Pitt, George Clooney, Jack Nicholson and Johnny Depp -- just to name a few.

What they all have in common is: nice looks, incredible talent, great scripts, sex appeal, and casting directors who picked them out of a huge talent pool.

We've watched these actors come into their own as they delivered their goods on the small and large screens. They all had to audition in the early days of their careers and each one had to keep the motor running from one project to the next, slowly building a body of work that became their ticket to stardom and eventually their legacy.

But why do these actors break out and others don't?

Here are ten actors who should have been big stars because each one has or had the "it" factor ... but what happened that stopped them just short of superstardom is anybody's guess. They are/were notable actors who should have become the next big thing in their generation.

10. Guy Williams -- Zorro, Bonanza, Lost in Space -- Guy Williams had the goods, but the Latin Prince Charming didn't have the roles over the years to project him into leading man status. Such a shame. I recently watched the five-part series of Bonanza where he played Will Cartwright, the handsome nephew of patriarch Ben Cartwright. Guy was supposed to replace Pernell Roberts (Adam Cartwright) on the popular Western but when Pernell decided to stay for one more year, he was written out of the series. He spent three seasons on Lost in Space (1965 - 1968) and retired to Argentina in 1973 where he reportedly died of a brain aneurysm in 1989. Look at his images here or watch "Guy Williams -- Behind the Mask."

9. Pernell Roberts -- Bonanza, Trapper John M.D. -- Pernell Roberts (aka Adam Cartwright) was one handsome cowboy who had some kind of power over me that I can't explain. I think it was the way he walked, talked, laughed, winked, breathed, kissed (on screen), ate, rode his horse ... just made me melt. He was a man's man, and a woman's fantasy. He should have never left the Ponderosa; big mistake because he was born to be a Cartwright. If he had gone directly into movies instead of doing regional theatre and guest spots on other TV shows, I think he would have been a matinee idol. His looks changed drastically between Bonanza (1959-1965) and Trapper John M.D. (1979-1986), but he still could have been one of People's "Sexiest Man Alive" candidates (kind of like Sean Connery, 1989). He passed away in 2010 of pancreatic cancer at the age of 81. Look at his images here and here (turn up the sound).

8. Troy Donahue -- A Summer Place, Surfside 6 -- In 1959 Troy Donahue was the breakout boy toy of the decade playing opposite future superstar Sandra Dee in A Summer Place. He was a teenage dreamboat who had all the makings of a leading man had he been given the opportunity. After appearing in the ABC television series Surfside 6, Hollywood began to deny his possibilities. His contract with Warner Bros. ended in 1965 leaving him in the dust. Those of us who had mad crushes on him back in the day were saddened by his death in 2001. Look at his images here or a clip from A Summer Place.

7. Richard Davalos -- The Americans, East of Eden (with James Dean) -- You've probably never heard of him, right? Exactly my point. This drop-dead gorgeous actor should have landed on the big screen in many movies. I remember being a kid and watching him on the TV show The Americans. My friend Brenda and I used to swoon! We squealed like he was Elvis every other week when it was his turn to be featured on this 1961 Civil War NBC television series. After it went off the air, we kept looking for him, but for an occasional guest-starring role on a TV show, he became a vapor. Why? He's now 81, living in parts unknown to me. Check out his images here or this scene from East of Eden.

6. Perry King -- Riptide -- Perry King has starred or guest starred in over 65 television shows/made for TV movies and 16 films since 1973. He played Cody Allen in the detective series Riptide (1984-1986) which should have set him up for bigger and better roles. Every time I would see him on the small screen, I thought that the next time I'd see him, he would be starring with the current female leading lady of the day on the big screen. That hasn't happened, so there's another glitch in the Hollywood system. See his images here.

5. Billy Dee Williams -- Brian's Song, Star Wars: The Empire Strikes Back; Star Wars: Return of the Jedi -- When I saw Billy Dee portraying football legend Gale Sayers in the 1971 TV movie Brian's Song, I was blown away by his performance. I just knew this talented actor was on his way to becoming a superstar as he transitioned into leading man status. Although he made over 36 films and guest starred in 55 television shows/series including becoming a cast member on Dynasty, he never quite became THE leading man he deserved to be. Take a look at his images here. If you want real proof of this actor's ability, please check out this moving scene from Brian's Song.

4. Jack Wagner -- Melrose Place, General Hospital, The Bold and the Beautiful -- When Jack Wagner played Dr. Peter Burns on Melrose Place from 1994 to 1999, I wanted him. There's an old song: "You Made Me Love You" that kind of sums up his ability to speak to women who have no business daydreaming. He had whatever "it" is so he could have carried that into the land of leading men so easily. He'll be front and center on Dancing With the Stars this season. Hold that smile Jack Wagner -- and dance into the hearts of every casting director in Hollywood. At 52, he's good to go. Take a peek at his images here.

3. Michael E. Knight -- All My Children -- Let's try to put the pieces of this puzzle together. MEK was the born to play Tad Martin on the ABC soap opera All My Children. He won three daytime Emmys for portraying Tad "the cad," Martin and rightfully so ... brilliant acting whether he was being dramatic or playing the class clown which made his character so much fun. He left the show on a couple of occasions to "pursue acting projects on the West Coast." Hmmm ... another one who shoulda/woulda/coulda. All My Children bit the dust in 2011. The versatile actor is only 52 so there's still plenty of time. Look at his images here.

2. James Brolin -- Marcus Welby, M.D., Hotel -- Where were the casting directors when James Brolin was young and debonair? Who failed to see the potential in this actor who could light up a woman's life with just a smile and a nod of that handsome head? He has been in numerous television shows and had some leading roles in movies over the years, but he was never the superstar he should have been. He's currently the best looking 71-year-old man I've ever seen. Look at his images here or his screen test for James Bond.

1. Tom Selleck -- Magnum P.I., Three Men and a Baby -- This is the biggest mystery of all. Tom Selleck was every woman's dream. I just knew he was going to take up where Clark Gable left off. Trouble is, that didn't happen. I offer no clues as to why but there must be a reason producers didn't hurl him into the likes of Brad Pitt/George Clooney status/stardom. He guest starred on Friends, and has acted in other television shows and movies here and there. The ruggedly handsome actor is now on the CBS drama Blue Bloods, but, at 67, it seems a bit late to play catch up. (Or is it?) I am truly baffled. He should have been one of the prominent leading men of our time. You'll find his images here or look at this clip from Her Alibi.