In quite a departure from their original stance on digital music distribution, Metallica is selling each of their shows from their current North America tour as a digital download.  I picked up the FLAC version of their Houston show for $13.  They also have MP3s for $10.  The quality is really good.  They have the right amount of crowd noise, and the balance between James and the band is good.

Browsing around their site, they also have 20 older concerts available for free download.