Ubuntu :: Backup And Restore A Triple-boot System?

best/simplest way to back up my triple-boot machine, which has Karmic 32-bit, Karmic 64-bit and Windows 7 (64-bit) installed on 3 equal slices of the internal 1TB disk. There are a total of 6 partitions (1 primary+1 logical partition each for the two Karmic, and 2 primary partitions for Win7), and I would like to back it up on an external disk such that the whole system can be restored as-is by writing over the disk. I guess this means correctly backing up data+partition table+MBR, and I would also prefer backing up only the used portion of the disk (rather than creating a 1TB mostly empty image file).

To my knowledge the only way to reliably do this is with "dd" command, but I have never used it ("fsarchiver" seems to be the next best option, but it cannot back up MBR yet; and "partimage" does not have ext4 support). As described here and here, I should run the following commands from a live boot:

1) To back up entire data in compressed format (using 1MB read block to speed up the process):

dd if=/dev/sda bs=1MB | gzip > /backup/image.gz

2) To back up MBR+partition table (stored within the first 512 bytes of the disk):
dd if=/dev/sda bs=512 count=1 of=/backup/image.mbr

3) To restore data:

gzip -dc /backup/image.gz | dd of=/dev/sda

4) To restore MBR+partition table:

dd if=/backup/image.mbr of=/dev/sda