Halo 2 was the only game that I ever went to a midnight launch for. Stood in line at a Gamestop for over 2 hours just to get my reserved copy. They were running a Halo tournament in the store at the same time, so it caused all the rest of us to have to wait forever.
And I probably wouldn't know a lot of the great guys I know today without Halo 2 and Podtacular. It's pretty much what got me into the community and podcasting.