Rob G. is 100% spot -on. Drive Image is the way to go, especially if you haven't done this before.
One thing I'd add is that DI's GUI is more user-friendly than Ghost's. It's not too clear exactly what you're doing in Ghost sometimes. I've seen a few Ghost horror stories were the user had backed up the destination partition onto the source partition and lost all their data! I've never heard of this happening with DI, I think because it's easier to use.