Once you've got your new SQL installation setup you have several options for migrating your databases. You've already mentioned backup and restore, there's also mirroring and log shipping too.

If you have a dedicated window of downtime and you're databases are not too big, you can just backup and restore the databases. However if you only have a short period of downtime and/or the databases are large, I would go with either mirroring or log shipping. The advantage of mirroring/ log shipping is that it can be setup before your planned migration so once you come to migrate, it is fairly simple to bring the databases on the new server online.

Here's some references:-

Mirroring - http://msdn.microsoft.com/en-us/library/ms189852.aspx

Log Shipping - http://msdn.microsoft.com/en-us/library/ms187103.aspx

Also, do NOT mirror/log ship any system databases. Any server scope settings should be scripted out and re-created manually on the new server.