HDD Folder oranization

How is everyone organizing their electronic data? I started out years ago with MS Outlook and hit the 2G limit early on so I ended up having to archive data monthly which resulted in a folder structure based around monthly archives like this:

2006
. Jan
. Feb
. .
. .
. Dec
2005
. Jan
. Feb

So I started following this structure and would store other files such as bank statements, pictures, invoices, etc in those folders. Problem now is finding anything I have to wait for a search to crawl through all those folders or remember when I did something or have some sort of index to it. I usually end up just hunting through the various years and months looking for what I want rather than keeping an index up to date so I'm looking for better suggestions as to how to organize inportant files.