Is the backup copied off the server to another location after completion (say to tape)?

If so its safe to overwrite the backup file on disk each night, Use a job executing a backup command with init rather than a maintenance plan.

If the db is in full mode and you are doing log backups you can also recover the database up to the minute using those.

Hyperbac is another tool which will backup the database to a compress ed file. easy and quick to install.