What's Better -- Serial Fiction or Stand-Alone Stories?

A friend of mine and I started chatting about Game of Thrones and I noted how amazing it was that it was staying so true to the novels by George R.R. Martin. I wondered how long it would take before the HBO series started taking some creative license with the series, straying off into different directions from the author's original source material. I had Showtime's True Blood in mind, a great television show based on the "Southern Vampire Mysteries" by Charlaine Harris. Would Game of Thrones also make changes for dramatic effect?

Martin's "Song of Ice and Fire," on which Game of Thrones is based, is a brilliant saga, but it has its flaws, especially if television producers are looking to adapt it as near verbatim as possible. It will be interesting to see where the fantasy show goes. So far, they have been bold in sticking with Martin's unflinching plot. But I expect that some changes will eventually be made, especially to address some of the criticisms fans have hurled at Feast of Crows, for example. Or maybe they'll find a way of combining it with Martin's latest, A Dance with Dragons.

Fantasy and science fiction tales often lend themselves to multi-part epics.  Publishers certainly encourage them, knowing that readers will come back for more once a great quest with memorable characters in a well-defined world has been established.  J.R.R. Tolkien, Isaac Asimov, C.S. Lewis, L. Frank Baum, Lewis Carroll, Arthur Conan Doyle, and Edgar Rice Burroughs all wrote serial fiction that captured audiences' imaginations. But some didn't -- George Orwell never felt the need to return to 1984 or Animal Farm for example. 

Hollywood has shown that there is money to be made in "franchising" stories. Mary Shelley did fine with one Frankenstein novel, but Universal Pictures struck gold by churning out sequels of her groundbreaking monster tale.

Some stories are structured to be told in numerous parts, but others feel like they were forced to fit a trilogy (or even longer series). Often, not all the chapters are made equal.

In the past, I expressed my wish that comic books focused a bit more on stand-alone stories. I also voiced my distaste for too many sequels and annoying prequels. The same can be said for literary sequels, those pre-ordained epic adventures that promise more books to come. They are almost intimidating to pick up and read, knowing that there are plenty more volumes on the horizon and that closure may not be attainable for a long while. How many of us can invest our time and effort to an encyclopedic series with no end in sight?

When done right, I enjoy returning to the familiar universes created by a great writer, seeing once again those characters I previously enjoyed as they now face new challenges. When done wrong, however, it can be brutal.  How wonderful would it be if these writers focused their energies on telling tales that have finite conclusions and then move on to brand new stories?