I spent a week and a half going through everything last July/August. I had never had any idea how many cars I had until I typed it all in. Each year from 1990-2007 has it's own sheet, all 80s cars on one sheet and all the earlier cars on one sheet. In addition, there are seperate sheets for Trucks, SCM kits, oddballs (Like event/track cars, color chrome, etc), other scale and several for my Customs. One of my favorite sheets is the stat sheet, where I have all the numbers for each season compiled in several diffrent forms, all with graphs to them. I also, during this project, figured out how many cars I have from each manufacturer (Racing Champions Basic leads the way with 1101, currently) and have that graphed as well.
All on Excel.
It's one of the best tools I've ever created...And, I had purchased several cars several times over, forgetting that I had already purchased them. That has not happened since I created my chart.
Also, creating the chart got me more familair with my collection, I now know every car, and more importantly, weather I have it or not.
My Advice: Create your own in Excel!