I'm a sucker for a well played classical guitar. Don't get me wrong I love acoustic steelstrings, and Leo Kottke is a special slice of awesome as is a good Dobro blues player. But I love the sound of nylon strings either played by a master like Segovia or Paco De Lucia.
This however is rocking:
That's right Metallica's Orion on acoustic guitar as a duet. Has nothing on Segovia or De Lucia in terms of phrasing or emoting- but it is fantastic. For more on Rodrigo y Gabriella check their entry on wikipedia.