How to archive a whole database?
You can save the index creation DDL statement and delete the indexes, to save more space before any archival path you choose. There's more advice on shrinking and fill factor here: http://www.brentozar.com/archive/2010/02/how-to-really-compress-your-sql-server-backups/

I've used option 2 to get better results than with the SQL built-in backup compression. Always start with DBCC CHECKDB ! Also take into consideration that your restore time will go up if you go on this path, as it takes a while to (de)compress with 7-Zip's best compression settings.