I began playing this game soon after launch. I've always loved superheroes and the idea of being able to make my own sucked me in. I didn't even know what an MMO was and honestly, I was crap at it. ;) My computer at the time was a laptop that could just about run the game (with massive rubber-banding and low FPS) but I played relentlessly anyway. Was living in London in a shared flat with people I didn't know and it was a way to escape and actually meet and talk to people. Because my toons were male, people treated me as male too which (long story short) helped me work out a lot of stuff that I was going through. 15 years later and I have fully transitioned, and while that probably would have happened anyway the community in CoX did a lot to give me the confidence to do it back then.
Amazingly, only 2 of my toons ever hit 50- my regen scrapper, Guide, and my emp/rad, Pink Champagne. I remember logging in once with Pink during the first Rikti invasions, and collecting a group of low-level heroes in Atlas Park and trying to keep them all alive until it was over!
I've played a lot of MMOs, some while CoX was still live and some after it was taken down. Even after CoX went, though, I've thought about it a lot. I still think it's the only create-your-own super hero game where I didn't feel like a pawn of some bigger hero or a nameless, pointless npc character of some kind. It also has some pretty amazing storylines in it, which surprised me the first time round and still does now. I think that's probably why this game has so many people who remember it fondly. I also love seeing all the characters people make, and the costumes. I used to spend a lot of time sitting on the bus shelter next to the trainer in Steel Canyon so I could people-watch and chat to my SG.
Still hoping to run into some old friends here at some point- but even if that never happens, it's amazing to see so many people online, enjoying the game all over again.