Haha!  Looks like a lot of people had the same 
idea.  I also use a color-coded excel workbook 
with formulas that tracks about 20 columns of 
data and statistics.  I also use mine as a 
database to store information about my cels that 
I am using on my soon-to-be-published webpage 
(ie. episode #, description, category, etc).

I even added a column that tells me which book 
each cel is located in.  This came after I about 
tore my hair out flipping through each of my 
celbooks trying to find a particular cel.  I 
don't like to overstuff my celbooks, so I have a 
lot of them.  I used to be able to remember, but 
after celbook #7 or #8 it became impossible.

I have to admit, I do not track my genga or 
separate background purchases tho'.  I'm not sure 
why - I guess it's because I never thought I 
would get that many, but of course my collection 
of those have grown over time too.

~ Luna-Art >^.^<