Master of Puppets is one of my favourite metal albums ever. I'm not a fan of thrash metal, the only real contender for the best thrash album ever is Arise by Sepultura.
Ranks:
1. Master of Puppets (pretty much perfect)
2. Load (I don't dislike any songs, + two epic tracks, Bleeding Me and The Outlaw Torn)
3. ...And Justice For All (aside production, a good album)
4. Metallica (I used to love it, but some songs just didn't bear the time)
5. ReLoad (not bad, some great tracks, but some fillers)
6. Ride the Lightning (don't like the production, and there are some songs I don't care about (Fight Fire, Bells, Trapped))
7. Death Magnetic (not bad either, but too long)
I haven't heard Metal Militia, so I left KEA out. It would be between ReLoad and RTL. And I haven't heard St.Anger.