Freeing up space and unaccounted for clutter...

I was wondering if there are any folders that have a lot of information in them that takes up a lot of space that osx10.4 takes up. Because I was going through my hardrive trying to see why i am running out of freespace. I went through Applications, Music, Movies and Pictures the folders and It looks like I still have about 50gb that is used up but i cant seem to find out where all of that is. I have a 250gb hardrive and have only been able to account for 180gb of used up space, but my finder says i only have 4gb left. Anyone have any ideas if this sspace is from the os or what, and if it is deletable?

-thanks

take a look at this app, it will show u where all the space went, and you can delete it right in the app

disk inventory X

http://www.derlien.com/

There's also JDiskReport

Real nice graphical representation of all your connected volumes and break down of space allocation.

Oh yeah,...it's free.