Better? No, why would it be? Your monitor may or may not be better than your TV, but if your PC is like mine it's one hell of a lot noisier than your TV. To me, watching DVD's on the PC is a little extra sumpin. But I have a recliner in my office, 5.1 speakers surrounding me, a 21" monitor. Even with all of that, I prefer watching movies on the TV in the family room.
Heck, you can get a DVD player to attach to your TV for $80, so why not get both?