A Good Slasher Movie?

Ok my girlfriend and I have been to blockbuster 5 times to search for a good slasher movie and 5 times and we have failed.
So what is a good slasher movie from the year 2000 until now?

Behind the Mask: The Rise of Leslie Vernon.
Starts funny but gets serious.
Disects the genre.
I highly recommend.

I also suggest Murder Party from 2007.
Very low budget. But very original.
Not technically a slasher, but plenty of slashing to go around.