Points worth noting -

For Backup/Restore

1> As the databases are on the same server, the necessity for moving data is not there. But, in future, if you plan to move the secondary database to any other system, network issues effect the process.

2> Each time you restore, scripts has to be run to take care of orphaned users.

For Replication

1> For transactional replication only the changes are migrated

2> All the tables for replications have to have a primary key.

3> You can have reporting services running on the replicated database

For Log shipping

1> Only the change move through the network (if on separate servers)

2> Reporting services cannot be setup

Copy database

1> Not recommended

There are other techniques using scripts and logic......which are tidious, time taking and needs thorough testing, but worthy enough

SP + SQL Job

Trigger

Hope this helps......