.gitignore file for Xcode 4/5

Original post on stackoverflow: http://stackoverflow.com/questions/49478/git-ignore-file-for-xcode-projects

My own forked gist (updated for Xcode 5): https://gist.github.com/curonian/6761653

-- Update --
Here's quick Terminal command to downloading this:

curl https://gist.github.com/curonian/6761653/raw/ -o .gitignore
git add .gitignore
git commit -m "Adding gitignore file"
git push -u origin master