Halo is such a great game, I easily forget.. Must have completed it in co-op with my best friend when I was what, 14-15, about 30-40 times. My mom even drove me and my friend about 40 kilometers (let's say about 25 miles) so she could buy us an extra controller, because we were always arguing over the only one I had. She didn't have that much money, but she still did it so we could play together. So beautiful.
We absolutely loved that game. We did pretty much everything possible, including stacking up as many grenades as we could find, must have looked for an hour while one of us kept watch on the Warthog so the grenades wouldn't despawn (some snow level was the best one for it). When one guy had the grenades, the other one killed him, and the grenades fell. Respawn and repeat. We did some epic, epic jumps, and also played the story a ton. 
I think this is probably my first gaming nostalgia moment, and it almost brings me a tear to my eye. So much fun, and so many memories I now hardly remember. Funny how you forget all the good stuff from your teenage years, and only remember the shit. 
 
 I also remember bringing my Xbox to my dads new house, where we could get broadband (before that I lived in the woods, literally, well, we had a house), and hooking it up to that tunneling service so we could play online. The lag was quite awful, but we had so much fun for the short weekend we spent there, pretty much staying up all night playing Halo. Too bad that the Magnum was insanely overpowered in Halo 1, so all the cool kids on that network just killed us and our local multiplayer skills easily.  
We used to have LANs for us two and two other guys, and play each other. Oh man, the fights, the shouting. Four teenage dudes with way too much testosterone, going at it, in a game as cheap as Halo. I became infamous for being the rocket launcher guy. They soon hated me.
 
Halo 2 was an immense disappointment for me. My friend, who had now bought his own Xbox to play Halo on (solely for this reason), were getting ready for the release of Halo 2. We both were pretty much exploding in anticipation, even though we at that point were a bit older. We lived about 10 minutes apart, now in the same city - no more woods. At the day of release, or when we expected it to drop in our mailboxes, we both skipped school and were gonna first play the campaign singpleplayer, to later meet up and do co-op. My game didn't arrive til about school was supposed to end however, so massive failure there. I was known for skipping school (WoW does that), so I got off fine, but spent most of the day getting excited texts from my friend who now had had it for about 5 hours, while  simultaneously walking around my room and going slightly crazy.
When I started playing I just felt weird. It wasn't the same game. It didn't live up to my expectations, and I kinda hated it for it. We still played some co-op though, and had alot of fun, even though I felt it was half as good as Halo 1. 
 
I did play through Halo 2 again a year ago on PC, and I absolutely loved it. Funny how hype can absolutely destroy a game that infact was really good. Halo 3 I sorta dug, but the singleplayer was boring and the story just tried too hard. I did play it alot in multiplayer though, almost three nights a week, with three to five other guys I got to know at work and previous friends from school. I was the best, probably still am, and man oh man did we have epic fights.  
At ODST's release I also played it with some other friends, drunk as hell, listening to Beyonce's Halo over and over again to much comic effect, while playing an epic four hour game of Firefight. Same deal with the singleplayer there though - tried too hard. 
 
I currently don't have a 360, but while writing this I discovered something I forgot - how much time I've spent playing games in the Halo franchise, and how much I do infact enjoy them. It's the perfect console shooter in my opinion (I tried MW1 for about 5 minutes, no thank you), and it always seems to grasp people that aren't really that in to games in general, so we can play multiplayer. 
 
And so I can stick them with a plasmagrenade, of course.  I think I have to buy Reach.