Turning books into movies is the most popular form of switching mediums, although you see the same with plays, comic books, television shows, etc. Adapting the work of a single writer (or sometimes a writer plus illustrator, inker, colorist, et al) into the work of many (screenplay writers, actors, director, producers, film editors, special effects gurus, et al) oftentimes means that nuance is lost. Probably fairly often you also lose the original motivation of the creator.
Perhaps the more interesting analysis is taking something in one medium and keeping it in the same medium. For example, you have the remake of "The Prisoner" that was running on AMC. You could also look at the new "Doctor Who" series, which is more of a generational reboot than a remake. There are also cultural remakes, such as "The Office," which was successful in the UK but exploded in popularity in its new American version.
This leads us all to this very interesting Slate article from a few weeks ago which discusses one of my favorite television programs of all time, "Life on Mars," and why the American version was so poorly received.
Britain is different in that they are content, in theory, to have a television program run less than five "series" (seasons for you and I). In contrast, with rare exception ("F-Troop," "Star Trek," etc.), American programs are deemed failures if they cannot go five seasons, the so-called bare necessary needed for syndication (this gives you roughly 100 episodes for the syndicated subscribers to cycle through). So while both "Life on Mars" programs actually had nearly the same number of episodes (16 for the original, 17 for the Yankee production), they had radically different resolutions, with the American counterpart scrambling towards the end to come up with a finale once the axe fell.
The U.S. "LOM" wasn't a bad show, but it wasn't on the same level of the U.K. version, and ultimately was lost with some other interesting ABC dramas like "Kings" and "The Unusuals," with solid concepts that apparently lacked mass appeal.