28 Days Later
28 Weeks Later
A post-apocalyptic zombie movie and it's amazing sequel. With the great news that 28 Months Later is scheduled for 2013, this franchise has followed George Romero's path while breaking new ground.
And for some reason I really enjoyed Robert Carlyle getting infected.
And yes, I know they're not really zombies, so these aren't really zombie movies. I just don't care.