If you are talking about files that belong to the UNIX underpinnings of Mac OS X: that's what locate is for, for example - try typing that into a Terminal window.
Maybe I'm doing something wrong, but when I start up Finder, there's no way for me to start from the root directory. So already, I'm not sure exactly where I am. Then when I start drilling down into directories, etc, there's only one of 4 views that will give me some sort of indication where I am, but not really. I have to concatenate all the directory names together in my head, as well as scroll left and right depending on how deep I am. I can't just cut and paste a location into the terminal window, and I find this really really annoying. It almost verges on useless to me.
-) This option makes navigation much easier, I don't know why it's not turned on by default:
http://macs.about.com/od/usingyourmac/qt/findertip1.htm
-) You can drag any file or folder into a Terminal window - simply drag and drop. You can also simply "Cmd+C" a file, go to Terminal and do "Cmd+V". The absolute path of the copied file will be inserted.
I think this can be turned off, and I think that at some point you turned it off... that's the only thing I can think of because getting to the root of a drive just requires going to the left of the window and clicking on the drive... most of the time (with the default finder configuration.)
1. Starting at the "root" directory. You can control what the finder window initially opens with on the General pane of the Finder Preferences. By default it should be your home folder (/Users/name).
2. Tracking your location. It sounds like you're not using the Path Bar. I believe it's disabled by default. Try View -> Show Path Bar. This presents your current location (in all view types) at the bottom. It also allows for navigational "jumps" to parent locations.
If you have OS X Lion you can open your Finder location in Terminal by enabling a Service in System Preferences -> Keyboard -> Keyboard Shortcuts. It's called "New Terminal at Folder" or "New Terminal Tab at Folder." See this Stack Overflow answer for more details: http://stackoverflow.com/questions/420456/open-terminal-here...