Showing everything on my HD?

[KevRC4130]

Hi guys,
Something happened with my Macbook Pro where although it's only a couple months old, its 500gb drive is nearly full, and that's before I even put my music on it! Clearly something is filling up the drive, but I can't seem to find it.

What's the easiest way to see exactly where my storage has gone? Ideally something with pie charts or something...

Thanks!

 

[spinnerlys]

Disk Inventory X, GrandPerspective and OmniSweeperDisk show where all the HDD space is gone to.