Actually, I set my lines DOWN to 65 characters. Years ago when I was doing Macintosh development, some of my co-workers had large monitors. I couldn't read their code properly, because it ran outside the viewing window on my smaller monitor.
I've got a nice wide monitor myself these days, but one thing hasn't changed: I still print on standard-sized paper. Wide lines either get truncated (losing data) or wrapped (ruining the nice pretty formatting). So even though I have sufficient screen space, I still keep the lines fairly narrow. 65 was a more or less arbitrary number that was somewhat influenced by the fact that I started on punched-cards, where the normal width was 72 columns.
Although I use the Java pretty-printer to enforce the text width, I also enable the "print width" option. It places a line down the editor view at the end of column 65 so I know
where things are going to wrap.
An IDE is no substitute for an Intelligent Developer.