Sure. Just wanted to make sure you have something backed up, just in case something goes wrong. You shouldn't need that anyways. But that's why all the people here recommend 'dd'ing the harddrive. This way you don't need to re-configure or install anything. It'll copy everything and just boot up as before.

Additional advice: Detach unnecessary drives before starting the process. That way you can't overwrite other things and it'll be just one disk to worry about. Buy a new drive that's the same size or larger. Expand the partitions at some point afterwards if it's larger, to access the new space. And after 'dd'ing a whole drive: Don't run the computer with both drives connected at the same time. The partitions will have the same identifiers, as it's an exact copy, and that might lead to confusing situations or the computer reading/writing to the wrong disk. Just detach the old drive after you're done and before booting again. You don't need that old hdd anymore. And use a Live CD / USB-Stick / Clonezilla to do it. Don't 'dd' the system while it's running itself.

I've done it several times. Worked very well each time. And it's not that much of an effort. Get an USB-Stick ready and install the new harddisk, 15minutes of work to get the copying started and then you just have to wait for it to finish, shut down, detach the USB-Stick and the old harddisk and you're pretty much done. It'll come up just as it was, just with a new harddisk inside.