Unless you are trying to save a few minutes then 'dd' is fine.

I personally use 'ddrescue' which you can get by running:
apt-get install gddrescue
The small benefit is that you can watch the progress and it will retry any errors it may find.
The useage is:
ddrescue /dev/hda /dev/hdb

Booting from a liveCD is a must but you seem to know that.

Make sure you know which disk is which to make sure you don't erase your good disk; there are *NO* checks. The command:
smartctl -i /dev/hda
will show you the serial number, or alternatively, with a modern liveCD you may find that:
ls -laF /dev/disk/by-id/
will show enough information to see which hd is which.