I've started using a command line tool called mackup to back up and sync many of my dot files and application settings on OS X.
brew install mackup mackup backup
By default mackup will back up your files to a file named mackup in the root of your Dropbox folder. You can also choose to back your files up to Google Drive or anywhere else on your local drive by creating .mackup.cfg in your user root and setting options the tool provides.
Now, when you move to a new machine, you simply install the tool and run:
Your settings will be added to the new machine and kept in sync via the storage you chose when setting up mackup.