I just redid mine, got away from a year/month folder structure to something that makes things easier to find. grr, forum takes out the spaces, had to replace with .'s.

/home/enine/Documents........................- this is where I put everything I create
.............|..........+-----Personal............- all my personal stuff, resume, etc
.............|..........|.............+---Projects - all personal projects I'm working on (not work/customer related)
.............|..........|.............+---Accounts - all personal bank/creditcard/etc accounts
.............|..........+-----Projects..............- everything I'm currently working on for clients/work/etc
.............+-----Archive..........................- all the completeld projects, old tax records, etc
.............|..........+-----Accounts..- bank accounts, credit cards, etc. Not under personal since they are all joint with my wife.
.............+---Info.................................- Should probably be called reference, all the pdf's, books, documents, etc that someone else has created and I have bought, dowbloaded, etc
.............+---Mail..................................- e-mail of course
.............+---Music................................- music ripped from cd
.............+---Pictures.............................- all my pictures, digacam or scanned
.............+---vmware.............................- vmware images of current testlab
.............+---iso....................................- iso's of trial cds for various trial softare, xp, 2003, etc for when I need to test things.

My design was based around making it easy to find things without searching or scrolling. The higher level folders are kept few enough that I can set the view to large icons and not have more than one page to prevent having to scroll around to see them all. This makes a simple "dashboard" where I can simply click on what I want to do.
First thing to do is repartition your drive, get your data files on another parition, this makes it easy for DR purposes as well as backup/imaging. Make something like D:\documents (get rid of the my space crap by editing the registry, its such a pain to have to put quotes in due to the space". Keep the folder names short and simple for ease of navigation or command line/script use. Then if you would even need to dual boot another os or put your drive in another box for recovery its much simpler. I am setup this way now, have a dual boot on my system with linux/xp and then the whole second partition is synch'ed with a small server each night and shared so my wife has access to the files or if my laptop would be stolen everything is right there on my server at home.
There are actually more folders but this should be ebough to give the idea. You may note that some are duplicated such as the projects folder under documents and under personal since I have projects that are just for me and projects for others so the whole structure of documents is duplicated under personal so when I had some non joint bank accounts that were just mine they were under \documents\personal\accounts just like the joint accounts were under \documents\accounts. So each follows the same workflow, if a project is completed or account closed it moves under the same structure under \Archive.
the only reason iso and vmware are at the top level is because it makes them easy to exclude form the backups, everything else is in the backups. those two folders are just so big it I don't have the space to keep them backed up anywhere.