IIIIITHE1IIIII on 25 June 2012
This may seem like a very random choice, but my favorite part (at the time, at least) would be the ending of mission 6 in Halo: CE. Uniting with all those marines and then fighting to get to the tower was an epic experience. There are lots of moments from Metroid Prime 2 (only borrowed the first one once) that are very close though.
A specific multiplayer part would be impossible to choose. There are countless heart beating moments that I've experienced from ranked team slayer (at the top ranks) and infection, among others.
