I didn't really play the first Halo until I got an Xbox in 2003, when I played the Campaign on Normal and dabbled in some XBConnect multiplayer. I didn't really seriously get into multiplayer until March 2005 in Halo 2.
I remember buying a Time Crisis game for PSX a couple weeks after the 9/11 attack and my dad giving me a hard time about it, asking sarcastically if I was going to go join the military since I liked shooting guns. I think he might have even eventually told me to stop playing it, it was making him so angry. It really sucked because I love light gun games, and I was really happy to finally have a somewhat cutting-edge one.
It's weird to think that Halo:CE launched just two months after the attack. I ended up buying a Gamecube w/Rogue Leader and Madded 2002. The console launch was a nice diversion following that tragedy.