Given the number of characters in the Star Trek franchise, it can come as no surprise that a vast number of actors have been considered for roles at one point or another. Because of certain castings, entire characters have been re-written to fit their new actors. In fact, I'm pretty sure that with the exception of Enterprise, the producers have had an actor in mind for the Captain of each Star Trek series and subsequently went with someone else. A couple of these are documented in this list, but for example, Alexander Siddig (then going by the name of Siddig El-Fadil) was actually the first choice actor to play Commander Benjamin Sisko on Star Trek: Deep Space Nine. It was only when they decided he was too young that they offered him the part of Doctor Julian Bashir and started looking for a new leading man. Some of these changes have been a result of aiming too high  going for actors who are too prominent already and don't want to commit to a series. Some are ongoing arguments with the studio who are pushing for a change in the attributes of a character. And some are just Gene Roddenberry disagreeing with all of his other Executive Producers combined. But that's Roddenberry's prerogative, it is after all, his show. Quite a few of these rejected actors went on to appear elsewhere in the franchise. For example, Tim Russ was considered to play Geordi La Forge in Star Trek: The Next Generation. He later had a background part in Star Trek VI: The Undiscovered Country and gained the main cast role of Tuvok in Star Trek: Voyager. Others will never be seen again in Star Trek. Like Wesley Snipes... who was also considered for the part of Geordi La Forge. Some stories simply don't have a great deal of substance to them other than being quite tantalising. Such as Sean Connery in Star Trek V: The Final Frontier as Spock's brother, or Tom Hanks in Star Trek: First Contact as Zephram Cochrane. Of course the J.J. Abrams films continue this trend, with Matt Damon, Adrien Brody, Joshua Jackson (as Kirk!) and Benecio Del Toro as Khan. So here are my favourite top ten stories from the twisty turny world of Star Trek casting. Needless to say that there are probably enough alternative castings to do a top fifty, but there are a sample at least. Hopefully I might have at least picked out a couple that most fans aren't familiar with, and as always feel free to leave comments below about other casting stories that you enjoy!