Probably most people run with High DPI monitors at 120 and above. This is a must if you have large widescreen monitors. Running at 'Normal (96dpi)' is not an option anymore as everything is to small to read on a widescreen monitor.

Most web sites still use low resolution graphics for much of their content. As a result running at a dpi of 120+ will produce blurry graphics if you use full page zoom to make things bigger.

Is it too difficult for web sites to query the users dpi and serve up appropriate graphics?

Just asking.