rsync is the best utility for mirroring parts of file systems.

I have created a script for uniform and convenient (IMHO of course) execution of rsync utility.
It shall be installed (copied) to /utils/ directory.

You can find and download an up to date deb and zip files with this and many other scripts at this address

sys_dirs.txt contains system directories excluded by default during system backup.

rsync.sh - a script for easy rsync operation
Syntax: /utils/rsync.sh OPERATION SRC [DEST] [NATIVE_OPTIONS]
SRC and DEST should look like [[USER@]HOST:]DIR

The script expects following values for the OPERATION argument:

system - backup excluding directories specified in sys_dirs.txt. It is useful for whole operation system backup.

data - backup data. Usefull  when copying from ext3 to another ext3 partition.

data_ntfs - backup data without permissions and omitting hard links

compare - compares source and destination (dry-run)

verify - verifies rdiff-backup checksums

NATIVE_OPTIONS let specify additional options corresponding to rsync

You can find more operation modes inside script by yourself. Please note that delete and delete-excluded options are not used by default to avoid destination corruption by accidental mistake. RSync works well even over sometimes unreliable internet channel.

Samples:
1. Backup a remote VPS system to your local /mnt/data/backup/vps/ directory:
/utils/rsync.sh system yourvps.com:/ /mnt/data/backup/vps/ -vi --exclude=/var/swap --delete --delete-excluded

2. Local server with a boot partition backs itself up to a remote storage-host:
BackupTo="storage-host:/mnt/data/backup/server1/"
/utils/rsync.sh system / $BackupTo -vi --delete --delete-excluded
/utils/rsync.sh data /boot $BackupTo -vi --delete

You can find and download an up to date deb and zip files with this and many other scripts at this address

As for incremental backups I suggest you to try ZFS on Linux and its send & receive commands, it is much better than rdiff-backup I used earlier.

Also see: Backup2DVD utility does VERY VERY SUPER RELIABLE backups to optical disks like Bluray and DVD, data on backup media survives small scratches due to high redundancy