Here are some of my all time favorites: (in alphabetical order)
2001: A Space Odessy -- Keir Dullea
6th Day -- Arnold Schwarzenegger, Michael Rapaport, Tony Goldwyn, Robert Duvall
Armageddon -- Bruce Willis, Ben Affleck, Liv Tyler, Billy Bob Thorton
Battle Beyond The Stars -- Richard Thomas, George Peppard, Robert Vaughn
Blade Runner -- Harrison Ford, Rutger Hauer, Sean Young, Daryl Hannah
The Blob -- Steve McQueen, Aneta Corseaut, Earl Rowe, Steven Chase
City Of Angels -- Nicolas Cage, Meg Ryan, Dennis Franz, Andre Braugher
Close Encounters -- Richard Dreyfuss, Teri Garr, Melinda Dillon
Contact -- Jodie Foster, Matthew McConaughey, James Woods, Tom Skerritt
Crouching Tiger, Hidden Dragon -- Chow Yun Fat, Michelle Yeoh,
Demolition Man -- Sylvester Stallone, Wesley Snipes, Sandra Bullock
Excaliber -- Nigel Terry, Helen Mirren, Nicholas Clay
Frequency -- Dennis Quaid, Jim Caviezel, Andre Braugher, Elizabeth Mitchell
Galaxy Quest -- Tim Allen, Sigourney Weaver, Alan Rickman, Tony Shalhoub
Hangar 18 -- Darren McGavin, Gary Collins, Robert Vaughn
Independence Day -- Will Smith, Jeff Goldblum, Bill Pullman
Invasion of the Bodysnatchers -- (Original B&W) Kevin McCarthy, Dana Wynter
Invasion of the Bodysnatchers -- Donald Sutherland, Leonard Nimoy
Jurrasic Park -- Sam Neill, Laura Dern, Jeff Goldblum, Richard Attenbourough
Ladyhawke -- Rutger Hauer, Michelle Pfeiffer, Matthew Broderick
Lord Of The Rings: Fellowship Of The Ring -- Elijah Wood, Viggo Mortensen,
(Cont) Orlando Bloom, Cate Blanchett, Liv Tyler, Ian McKellen
Lord Of The Rings: The Two Towers -- Elijah Wood, Viggo Mortensen
Lord Of The Rings: Return Of The King -- Elijah Wood, Viggo Mortensen
Lost In Space -- William Hurt, Gary Oldman, Matt LeBlanc, Mimi Rogers
Mad Max -- Mel Gibson, Joanne Samuel, Steve Bisley
Matrix -- Keanu Reeves, Carrie-Anne Moss, Laurence Fishburne
Men In Black -- Tommy Lee Jones, Will Smith, Rip Torn, Linda Florentino
Men In Black II -- Tommy Lee Jones, Will Smith, Rip Torn, Lara Flynn Boyle
Metropolis -- Alfred Abel, Gustav Froelich, Brigitte Helm
Millennium -- Kris Kristofferson, Cheryl Ladd, Daniel J. Travanti
Short Circuit -- Steve Guttenburg, Ally Sheedy, Fisher Stevens
Stargate -- Kurt Russell, James Spader, Jaye Davidson
Star Trek (All) -- William Shatner, Leonard Nimoy, Deforrest Kelly, James Doohan
Star Trek TOS -- William Shatner, Leonard Nimoy, DeForrest Kelly, James Doohan
Star Wars (All) -- Harrison Ford, Carrie Fisher, Mark Hamill
Terminator -- Arnold Schwarzenegger, Linda Hamilton
Terminator 2: Judgement Day -- Arnold Schwarzenegger, Linda Hamilton
The Thing -- (Original B&W) James Arness, Kenneth Tobey, Margaret Sheriden
The Thing -- Kurt Russell, Wilford Brimley, Keith David, Donald Moffat
Volcano -- Tommy Lee Jones, Anne Heche, Don Cheadle, Keith David
War of the Worlds -- Gene Barry, Ann Robinson, Less Tremayne
Waterworld -- Kevin Costner, Jeanne Tripplehorn, Dennis Hopper