I'd say 25% of my DVDs are unopened. I bought them all in anticipation of viewing them while my wife was pregnant but we ended up not watching alot of them because she didn't want to see anything violent.
Most of them are older movies I got on sale like Wargames, Excalibur, Red Dawn, etc. But I've got quite a few new ones she didn't want to see like the Patriot, Braveheart, Last of the Mohicans, Spartacus, etc.
I don't know if I'll ever catch up to watching them.
Edit: I must have like 80 DVDs with about 20 unwatched and unopened.