I was previously using the top-voted answer, but it needs a bit of cleanup, so here it is redone for Xcode 4, with some improvements. I've researched every file in this list, but several of them do not exist in Apple's official Xcode documentation, so I had to go on Apple mailing lists. Apple continues to add undocumented files, potentially corrupting our live projects. This IMHO is unacceptable,