Many times, I get calls from frantic folks who are almost out of hard disk space on their system, and don't know what to clean up, or where all their space has gone.
Keep your drive tidy
The Windows XP clean-up wizard is a nice start by clearing out temp files, cache, recycle bin, etc. - but it's not really telling you anything with regards to where your large folders/files are located.
This is where TreeSize Free comes in. Little brother to Jam Software's TreeSize Professional/Personal, TreeSize Free can give you a quick overview of what folders and files are consuming the largest percentage of your drive space in a nice graphical treeview format.Find all MP3 files? Sure thing.
This is a no-frills program, so not many options are available. However, with that being said, there's not really much more needed for the casual user. I especially liked the ability to filter for particular file types (if you want to see how much space overall your mp3 files are taking up, for example).
Another nice but seemingly trivial addition is the ability to right-click your folders and explore them from a new explorer window spawned from the TreeSize interface. The program really is so easy to use, adding more features to it for some people might be overkill.
You can only scan locally attached drives, which shouldn't be a major issue with most home users.
If you are a network administrator and need export capabilities, charts, and overall statistics about what is on that share or hard drive, then I would recommend the pro version (also VERY nice). However, if you are a person who supports home users or other folks that are concerned only with their local hard disk space, then this is the program for you...