My friend and I just finished Halo 2.
Indeed, it really does have one of the worst endings in the modern era of video games. Instead of feeling exhilarated and satisfied when I finish the game, I felt only disappointment. Combine that with the game also being far too short (even on Heroic) and that we won't even see the sequel on the same console (not even mentioning that it'll probably be yet another 3 years away), and I'm left with only a bad taste in my mouth.
Kind of like two-day old vomit.
No idea what I'm going to tackle next.