Might as well share my own: My commander Shepherd was a ruthless earthborn who knew the value of sacrifice. Her only goal was to make life for others peaceful by eliminating any threats. My favorite choices were killing Mordin (I really like his character and liked to think my Shep and him were good friends) and choosing the sythses option. Both highlight her will to sacrifice and her goals. The reasons she chose synthsies instead of destroy is because it may right her wrongs (like dooming the krogan)
Side note: she was a glow stick for ME2 and ME3
