Xcode Hangs at Startup

Xcode fails to open on my machine – OS X 10.8.2. It opens the main screen and just hangs there with the spinner spinning becoming unresponsive. If I double click a project, it just hangs sating it is loading.

I tried:

1. Uninstalling and re-installing;
2. Removing my project tree;
3. Deleting some recommended preferences, most of which did not actually exist on my machine to begin with.

Things of note:

1. This is a new computer. The first time I ran Xcode, it opened fine, though I didn't try using it. The problem appeared when I first opened an existing project.
2. I created a new user on the machine. When that user is logged on Xcode loads successfully. Apparently it is a user settings issue.