Newbie question on getting back hard drive space
Solution 1:
Disk Inventory X or WhatSize are both excellent apps for giving you a complete list of what's taking up space. Also, as you described there is a way to start at the root and check the size of each folder, drilling down until you find the culprit. Command-I or Get-Info from the the right click menu will show you the size of any folder or file you select.