We had someone that once posted a Superman Vs Goku thread. You're not that same person are you? It was a fun discussion.
PS you might really enjoy these guys on youtube "Death Battle!" http://www.youtube.com/show/deathbattleOn Topic
I like Darth Vader way more, but Voldemort is a sorcerer and should be able to easily subdue and destroy the movie Darth Vader. Vader has to concentrate to much to make his powers work and he doesn't have the ability to expel force lightning or anything.
On the other hand...
The book Darth Vader (especially the Luke Skywalker as Vader would destroy Voldemort) as the book Vader is fully capable of almost all force related powers. He's also fought an endless stream of battles, wars, and duels that places him well ahead in training and experience. Voldemort is a manipulator, not a warrior. With no time to prepare, Voldemort would be outmatched, ill-prepared, and without his best tools (cheating, lying, manipulating, and his armies of cronies.)
Edit - Oops, I forgot to include:DEATH BATTLE! - Luke Skywalker VS Harry Potter