These are my two personal favorites. They were so awesome that I had to watch them again on Youtube. I haven't finished the game yet, but I've heard some pretty bad things about the ending. I hope it doesn't ruin these. What are your favorite cutscenes in ME3?
http://www.youtube.com/watch?v=KrH0Lda0Hds
http://www.youtube.com/watch?v=k9z2TkVNWlM
Honestly, I think they're among the most epic scenes in videogame history. The music, setup, and little amounts of dialogue were just so perfect. I honestly cried while watching the first one when I was playing.
"My turn."