I'd have to agree that it's just easier to alter your user settings than changing the default for everyone. I personally like 70 right where it's at, as I come to this site from about five different computers, featuring resolutions from 1152x768 to 800x600 (laptop, and it's not even an active matrix screen, ugh).

I turned off wrap for awhile and it screwed up the Monastery Gates consistantly, I couldn't figure out what the heck was going on for some time - 70 seems like a great default.

~Brian