Best opening track on a rock album?

Some albums hook you from the very first song.

What's your favorite album opener and why?

A few examples:

• Welcome to the Jungle
  
• Battery
  
• Black Dog
  
[*]Smells Like Teen Spirit

battery is a strong pick but for me it’s gotta be black dog. that opening riff is so gnarly and sets the tone for led zeppelin iv perfectly. it’s like they’re daring you not to keep listening plus the way plant’s vocals weave in and out of the groove? chef’s kiss.