I think the general consensus is that the representation break down on the storage allocation in About this Mac is not even close to being accurate. Furthermore the software's identification of "Movies" is not counting what's in your Movies folder but rather additional application support files and such. The good news, the value where it says 40.34 GB free of 120.47 GB is accurate.
If you're looking for an itemized break down of what's where, I'd recommend a 3rd party application. An example of a few are:
- Daisy Disk
- Omni Disk Sweeper
- Disk Inventory X
All of them are free for the purposes of scanning and displaying results, a few of them require you to pay if you want to enable additional application functionality.
Here's a link to more information regarding local Time Machine snapshots - http://support.apple.com/kb/HT4878