Baph

There's a couple:
The Descent.
Saw.
The Ring (original Japanese? version).

If we're including scary/funny films, then:
Hellraiser (pick any from the series and you're on to a winner)
The land of the dead.
28 Days Later (a couple of scary moments in it)
28 Weeks Later (as above).
Resident Evil (although a bit tacky, which made it funny).

There was also something I went to the cinema to see not that long ago, but can't for the life of me remember what it was. I know it was a scary movie, but don't suppose it qualifies as "favourite" if I can't remember it.

Can you tell I like "scary" films?