Click on "All My Files"
You should be able to see all your audio, movies and photos. (Click show all).
Other referes to all kinds of files that do not fit into the other categories.
They could be anything from system files, to files created by apps, to things you downloaded from the internet such as pdf files, text files etc. Anything. That's why it is called "Other" since it is general.
I have 67.45GB in other.
Ultimately, you may want to perform a complete do over--which given your circumstances might require you to perform a clean install. More on that later if you want to do so eventually.
I am assuming you transferred your data, etc., from your iMac using either Firewire Target Disk Mode for over a network. It doesn't matter much, but which did you do.
Regardless, for now, I would do a repair install of Lion and see how things look after doing so. A repair install should leave installed apps, files, and settings alone. And, such an install very well sort out any issues of how much of what you have where. There are several ways of doing so. first, if your Lion Recovery HD partition is present or you have set up a Lion Recovery Disk Assistant, then either will work. Let's see if you can do either of these before going any other route.
Try starting up holding down the option key. Once done, see if there is a "recovery" option. If yes, then I would choose it and ultimately choose to reinstall Lion from the Apple site. If you have unbacked up files, etc., then be sure and back them up to your iMac before doing any kind of install.
If you want to read more about what I am talking about, then go here (read from the top).