For me, it’s secret identities and the return of the missing heir. I’m drawn to these plotlines like a moth to a flame, and it’s part of the reason, I think, that I find epic fantasy so often satisfying. These are common themes in fantasy, though they show up in mystery and other genres as well.
What plots/themes are you inexplicably drawn toward?
I have an affinity for wacky ensemble comedies. Just about anything from Arrested Development to Night Court has been my favorite at one time or another. Even It’s A Mad Mad Mad Mad World, which really isn’t that funny, is still pretty funny.
I like consummated romance: not kiss-sex, not endless yearning, but building a real intimate relationship. Guess how often that happens in movies.
This is one reason I like tvtropes so much-- some of the plots I like are:
– battle of wits type situations (Death Note, The Enemy Below, The Butcher’s Boy)
– the (mis)-adventures of a character with extremely good luck (Ringworld, The Irresponsible Captain Tylor, Intacto)
– elaborate prison breaks or other plans (Prison Break, Escape from Alcatraz, The Count of Monte Cristo)
– anything that involves plans that tvtropes calls Xanatos, be they Gambits, Roulettes, Speed Chess, etc. (specific episodes of Veronica Mars and House, Runaway Jury)
– obsession (Moby-Dick, The Love of Stones)
It seems that looking for similarities like this is much more difficult for a recommendation program, so tvtropes is kind of what I have been waiting for my whole life. It’s not perfect but it’s got the right idea.
I love a good apocalypse.
If it’s apocalyptic or post-apocalyptic, I’m there.
I particularly like anything that explores the changes in human/American society and lifestyle on earth after some time has passed since the apocalypse. Or since some major development or change, even if it wasn’t exactly an apocalypse, such as massive overpopulation or or environmental degeneration or something.
Fortunately, this is a very common theme, so there’s lots of material out there. The problem is that sometimes, if I take in too many apocalyptic stories in a row, I get kind of depressed.
I love things with the theme of “you thought you left this behind you, but it’s been with you all along,” or more simply, “you can’t escape yourself” (the movies Unforgiven and Open Range are good examples).
Also, books with shy or introverted heroines who fall in love with distant, forbidding men above their station (Rebecca, Jane Eyre, Moonraker’s Bride, Mary Reilly, The Perilous Gard, etc.).
And anything prominently featuring a sinister minister/priest (The Monk, The Night of the Hunter, The Hunchback of Notre Dame, Carnivale, and the music of 16 Horsepower) is like chaste pornography to me. That’s my all-time favorite character type.
ETA: And things where your two protagonists suddenly find themselves pitted against each other with life-and-death stakes. The X-Files did this a lot, where Mulder and Scully would end up with their guns pointed at each other in really emotionally intense situations. Love that stuff.
Ancient prophecies.
Saving the world.
Ancient prophecies about saving the world.
Tricksters, in all their delightfully dishonest flavors.
Really powerful, awesome (in both senses of the word) magic and magicians.
Can you guess what my favorite genre is? 
I love love love ‘ordinary man forced to become spy/investigator in hostile situation’.
Heist films. I love the puzzle nature of a well done one: the planning, the assembly of the perfect team, the execution, dealing with complications that arise, etc.
I can’t seem to put down any scifi novel that involves specialized body armor; *Forever War *by Haldeman or *Armor *by John Steakley are two good examples.
We should start a recommendation thread based on this thread.
I love the classic “two people who despise each other are thrown together for a common cause” sort of plot.
I’m fascinated by plots where a semi-evil person redeems himself by coming to the rescue, or where the weaker party rallies to save the day. (Riddick going back to help at the end of the movie Pitch Black. Sunshine and the vampire helping each other in Robin McKinley’s novel.) I also like a gender role reversal, where a man is depending on a woman to save him.
Anything that ends badly for everyone like most Rainer_Werner_Fassbinder
Snooty, evil, selfish, wicked people getting their comeuppance – everything from The Little Foxes and The Women to Heathers, Trading Places and Working Girl. One of my favorite Bewitched episodes had Samantha at a dinner party, putting spinach between teeth on a hoity-toity bitch who was after Darrin.
Also, people living someone else’s life, assuming another identity, either accidentally (While You Were Sleeping) or on purpose (Bette Davis in A Stolen Life).
Also apocalypses.
Zeppelins
Stories where the lead character is a morally ambiguous trickster… like Captain Jack in Pirates of the Caribbean.
Second post-apocalyptic movies/books.
Also, embarrassingly, supernatural romances.
Psychotic serial killer novels and novels with seriously flawed protagonists, such as the James Lee Burke series or the Elmore Leonard novels.
Post-apocalyptic scenarios with gratuitous bisexuality.
Schemes, mindgames and manipulation. The more ridiculously contrived the better.
Excellent choice. I love a good heist flick.
The other type well-represented on my list of all-time favorite films is: biographies of extraordinary people. Patton, Amadeus, Lawrence of Arabia…even Searching for Bobby Fischer (the protagonist is extraordinary – just not famous).