Would I be able to restore this image on a larger hard drive? - Yes, you can do this. I suggest you get your new drive, use something (see below) to migrate your data and then only destroy the original data once you've confirmed the copy worked perfectly.
CloneZilla is a decent option.
I also like to use GParted for these kinds of things.
If you happen to be dealing with OSX, then the Disk Utility (Applications > Utilities > Disk Utility) is profoundly helpful. Note that "Disk Utility" is also available on the OSX installation Disc, so you can boot from that and run it, if you launch it before clicking too far in to the installer.
If you like to spend money on things, you may also want to look at Norton Ghost for this.