[PLUG] How to make a complete copy of a partition?

[John Jason Jordan]

OK, my Bonobo Extreme is the most bad luck computer I have ever owned.
First the soda in the keyboard incident, and now the video issues. But
at the moment it is running, so it is time to make a complete backup.
The partitions to be backed up are / and /home, separate partitions on
a 480 GB SSD, which also has two discontinuous free spaces. I don't need
the free spaces, but I want a copy of both partitions such that, come a
disaster, I can simply restore them from the backup. I think the word I
am looking for is "clone," or maybe "disk image." 

I use rdiff-backup with a script to back up key parts, but here I want
a complete copy.

The destination will be a 3 TB USN 3.0 external drive. It has about 1.5
TB free space on it. 

I have heard of dd, but I know little about it. Before I invest a lot
of time struggling to understand its man pages, is this the best tool
for what I want to do? Or are there better choices?