If you’re tired of Twitter and you want to leave this site forever, then, if desired you can make a total export of all your tweets. The easiest way to do this is through the service twDocs.
The service supports exporting to PDF, DOC, XML, CSV, TXT, XLS and HTML. Archive logs all messages, including personal ones.
The default number of messages for export is limited to 200, but you can increase this number to 3200.