Users in City of Heroes are planning memorials. On the server I play on a number of high-level players will be standing near the costume shops, giving away money so people can change their costumes to black. Others are dropping their capes or adding an "S" to their outfits. It sounds like a silly gesture but this man is part of the reason so many of us play.
At one time Superman 2 stood as probably the greatest movie of the "super hero" genre, and I have to say that Christopher Reeve is linked indelibly in my mind to Superman. I saw those movies in the theater, and I remember them fondly.
Of course, he did other things, too. I remember him from "Remains of the Day" and "Somewhere in Time". not just for being Clark Kent.
Seems like Christopher Reeve's name came up every time someone mention spinal injury or stem-cell research. It's silly that we need someone famous to remind us of human suffering but, really, before his accident, how often did anyone talk about about those things?