Leia Organa Solo
I don't particularly like Princess Leia. I'm not going to pretend I do. She's a brat, she's stuck-up, and she's rude to Han before even learning his name. (Oh, sure, *later* they get married and have kids, but he's WAY to good for her.) That's just my opinion, though.

Her adoptive father is Bail Organa, the leader / ruler of Alderaan. (No one knows much about Alderaan, I think. At least *I* don't.) Her real parents, Queen Amidala and Anakin Skywalker (if you haven't figured this out...you must be blind!), seem to have some problems (Dark side, anyone?) and she's separated from her twin, Luke, presumably shortly after birth. She remembers a bit about her mother, so I think Amidala stayed with Leia.
In A New Hope, her ship, the Tantive IV, is captured by Vader above Tatooine, trying to find Obi-wan Kenobi, after getting the secret transmissions from Rebel spies. She hides the Death Star plans in R2-D2. Leia is then transported to the Death Star (Cell block 1138, I believe) and is interrogated. Even when threatened with the destruction of her home planet, she refuses to surrender the location of the Rebel base.
Meanwhile, Luke meets Obi-wan, Han, Chewie and they end up on the Death Star. After Obi-wan leaves, Luke learns that the princess is onboard. He coerces Han into aiding in her rescue. Pretending Chewie is a prisoner ("Where are you going with that...thing?" "Prisoner transfer..." "I wasn't notified.") the group infiltrates the Imperial cell block and kill everyone (whilst also shooting *everything* in freakin' sight!). They free Leia ("Aren't you a little short for a stormtrooper?") but manage to cut off their "only escape route." So Leia blasts a hole in the wall and they drop into the garbage shute ("Get in there you big furry oaf, I don't care what you smell!").
Oh dear! Our heroes are going to be "a lot thinner." But, no, Luke contacts C-3PO and he then "shuts down all the garbage mashers on the detention level!" Yay! After a few snide comments with Han, and insulting Chewie (He is NOT a carpet, thank you!!!), Luke and Leia split off from the rest. Stupid Luke blasts the lock on a door and they get stuck at the edge of a precipice. Leia isn't much help yelling at him to do stuff he can't. Then he gets a genius plan to swing across. They do so (*ignores incestuous relationship hint*) and get to safety. Leia, Han, Luke, and Chewie escape the Death Star. They get to Yavin 4 where the plans prove to be invaluable. Leia stays behind whilst Luke and Han blow up the Death Star, saving the day.
Way later, in the books, she and Han get married and have three children: Jacen, Jaina, and Anakin. (Jacen and Jaina are the older twins.) She also becomes the Cheif of State of the New Republic when Mon Mothma retires.
That's all for now...