Fionnula Flanagan's scene-stealing guest spot on the "Flashes Before Your Eyes" episode of Lost got me thinking about some of the other memorable guest stars the show has had over the years. It was difficult to commit to only five performances, with so many to choose from. Below are my picks for the most entertaining guest roles over the last three seasons.

1. Clancy Brown ("One of Them"; "Live Together, Die Alone"): This actor owns every role he plays, from Brother Justin in Carnivale to Byron Hadley in The Shawshank Redemption, so it was no surprise when Clancy Brown rocked both Sayid's and Desmond's flashbacks. It is still unclear if Joe Inman and Kelvin Inman are the same person, but at least one of them has a major role in the history of the DHARMA hatch. Here's hoping that Inman's (and Brown's) part in the Lost story continues in the future.

2. M.C. Gainey ("Exodus, Part 2"): Tom appeared in later episodes, but I am counting his first episode as my favorite. For my money, there was nothing more disturbing than when Gainey showed up out of the blue and uttered the words, "We're gonna have to take the boy." I could not get that scene out of my head for days after "Exodus" aired. Ben has made Tom seem relatively less menacing over time, but I have a feeling that the terrifying, bearded sea captain is still in there somewhere.

3. Kim Dickens ("The Long Con"; "Every Man For Himself"): Dickens' quiet and understated approach to her roles served her well on Deadwood, and she was just as successful in her portrayal of Cassidy. The characters in Sawyer's flashbacks have mainly been bland, criminal underworld types that failed to add depth to his back story. Cassidy, however, gave viewers something beyond revenge and self-loathing with which to associate Sawyer.

4. Kevin Tighe ("Deus Ex Machina"; "Orientation"; "Lockdown"): Anthony Cooper is one of the worst fictional fathers since Darth Vader, and only Kevin Tighe could do the part justice. An organ-stealing parent sounds more appropriate to a soap opera than a prime-time drama, but Tighe's subtle performance kept the role from being cartoonishly evil. I still wonder if Cooper will turn out to be the original Sawyer.

5. William Mapother ("All The Best Cowboys Have Daddy Issues," etc.): Ethan Rom gave us our first look at what the Others are capable of, and he made quite an impression. In a single episode, Ethan kidnapped Claire, threw down with Jack, and literally left Charlie hanging in a chilling near-death scene. The show's writers have tried to make some of the Others more sympathetic, but Mapother's creepy portrayal of Ethan still serves as a reminder of the dark side of the Others.

Who are your favorite Lost guest stars? Feel free to post in the comments below.