I think it's pretty certain we have a few launched careers from Lost, (a couple had already been launched, but now more so) but what's less clear is what they will do with it. It's a hard guess going from the show, becuase I"ve found in the past that when I guess at such a thing, I tend to extend from the character they played in their hit, but this is dependant on how it was written, and how they were directed, and doesn't give enough scope. But it's fun to guess, and if you watch interviews you might have a better guess.
Here's some totally unsubstantial examples to get things started, but I"m curious what you think more than I am my own ideas, as it's more that I wonder than that I can visualize the answer:
Jorge Garcia (Hurley): Coming of Age Comedies or Sitcom (but I would like him to be in movies made from Greg Egan novels)
Evangeline Lily (Kate): Standard Hollywood Dramas
Josh Holloway (Sawyer): Action Flicks (again, I want to see him in Greg Egan movies... an no there is so far no such thing as a Greg Egan movie)
Terry O'Quinn (Locke): Movies requiring solid acting and general acting awesomeness, usually an everyguy (maybe secretly a murderous stepfather)
Jeremy Davies (Faraday): Horror
Elizabeth Mitchel (Juliet): I predict Television Sci-Fi (heheh)