Amy Pond had such an amazing storyline it's hard to know where to begin with her.  She was brought to us initially as a young child played by Caitlin Blackwood and then most iconically by Karen Gillan.  She was the Girl Who Waited.  She first joins the Doctor in 2010 and stays with him until 2013 during which time she marries Rory, gets kidnapped, continues as a ganger, gives birth to Melody, has her kidnapped, numerous other adventures and finally her and Rory get touched by Angels but manage to live out their lives happily into their 80's!