I have ninety-some odd DVDs in my collection. I can't get an exact number because I count 90 on my shelf, and I know that I have a handful that I have loaned out to people. No one bothers to tell me when they borrow my DVDs, so I don't even know which movies I'm missing.
I've been trying list my collection in
Delicious Library, a rather nifty program for OS X that you can organize books, movies, and games in. If you have a webcam I hear it's possible for you to actually scan barcodes and have the program automatically list whatever you scanned.