Judas Priest - Unleashed in the East
I was introduced to this album through a reviewer on Metal Archives named UltraBoris. Looking back, it's clear he was passionate about metal but more than a little stupid. He was right about this being the best live album ever, though -- don't listen to the naysayers who wallow that Halford rerecorded the vocals; supposedly the unaltered recording sounds the same except for equipment errors. Anyways, this album just rips. The best of Priest's 70s material (read: Priest's best material except Painkiller) with better guitar tone, extended song segments, intense performance, and a few hundred screaming Asians. If you like Priest even a little, get this album.
As for extreme metal, I don't really listen to live albums very much... The "Live Madness '89" DVD that came with the most recent Altars of Madness pressing is pretty sick.