I like a lot of the people in the Rebellion, like Wedge and Mon Mothma, but my favorites have to be Bail Organa and Luke Skywalker.
I like Bail Organa for many reasons- he's a good politician, he does the right thing, and is a good person. He risked his life bringing Obi-Wan and Yoda to Coruscant and seemed horrified when he saw Zett Jukassa(Jedi Padawan) shot down by members of the 501st. He also help start the Rebellion against the evil Empire and raised Anakin's daughter, Leia. And it is really sad when you realize he was killed during the destruction of Alderaan :(.
I like Luke also for many reasons. He's a powerful Jedi(DUH!), he's my favorite character in the Original Trilogy, he's a good person, he destroys the Death Star, AND he redeems his father, thus helping defeat Sidious, and restoring peace to the galaxy. Both these men are pivotal in Rebellion, one started it in the early days of the regime, and one helped to bring that regime down. All in all, two VERY important people. :)