If we're going to deal with all of the variations of Star Trek, let's just get this one out of the way:
Wesley Crusher, Star Trek: The Next Generation
On a ship with a crew of supposedly about a thousand people or so, including an android that made Mr. Spock look as smart as George W. Bush, there were too many times that the survival of the ship depended on this kid. It was beyond annoying; which is probably why millions of television sets had to be replaced due to gunfire damage from ST:TNG fans.
I could not think of any fate that probably wasn't discussed to death on alt.wesley.die.die.die back in the text-based Usenet.
(This is all separate from Wil Wheaton, who has his own blog, an older blog and is apparently a pretty decent guy. As a bonus, he opposes the Chimperor, so I feel kind of bad for piling on his signature character, but I'll get over it.)