I think Delicious Library is basically this, but it's Max OS X only. Wikipedia lists MediaMan as a Windows equivalent.
Disclaimer: I haven't used either. I went through a similar phase when I first started ripping my DVD collection, hunting down or scanning in cover images and generating nice icons from them, but these days I don't bother any more and don't miss it.
The one I use for my movies, books and CDs is MediaMan. Costs a bit of money, but overall it's been worth it.
After inputting everything (you can use a webcam as a barcode scanner), I've used it to keep track of what I own, what I lent out, which are my favorites, etc. It did take a while to put everything in, but ever since then, my life's been a lot easier (and I'm not buying multiple copies of everything).
Not affiliated with this program in any way, btw, I just found it to be the best.
If you want to catalog your DVDs and books, you might check out an app such as Delicious Monster, which can read bar codes with a webcam and fetch the details from the web. Unfortunately, Delicious Monster for iPhone was removed from the App Store because Amazon objected to being used as the source for those details. MediaMan is reputed to be a similar app for Windows.