This happened to me as well several times.
The fix is to delete all the Xcode plist files in Library/Preferences. I have no clue why this fix the problem, but after having to do this a few times I know that this at least fix the problem short term.
PS - The crash also happened to me when creating a new file - not only a new project..
How do you do that? can you share some screen shots on how to Delete the plist for Xcode
In the Finder, use the Go/Go To Folder menu with this string: ~/Library/Preferences
When that Finder window opens, use the 'search' input box up on the right to look for (name matches): com.apple.xcode
Delete the couple files it should locate, then restart Xcode...it will build new ones.
There's a terminal command too, if that floats your boat, in which case, google is your friend.