This is a good list you've made It's interesting how you've opted for a period of time, in this instance the early 90's, which to me is one of the most interesting periods in metal, as opposed to a yearly ranking. This makes listing that bit more challenging to rank.

Here's my personal ranking from 1990-94:

1. Megadeth - Rust In Peace
2. Judas Priest - Painkiller
3. Slayer - Seasons In The Abyss
4. Bathory - Hammerheart
5. Mayhem - De Mysteriis Dom Sathanas
6. Emperor - In The Nightside Eclipse
7. Bolt Thrower - ...For Victory
8. Dream Theater - Images And Words
9. W.A.S.P. - The Crimson Idol
10. Running Wild - Black Hand Inn
11. Tiamat - Wildhoney
12. Skyclad - Prince Of The Poverty Line
13. Sanctuary - Into The Mirror Black
14. Iced Earth - Night Of The Stormrider
15. Blind Guardian - Somewhere Far Beyond
16. Necrophobic - The Nocturnal Silence
17. Carcass - Heartwork
18. Dismember - Like An Ever Flowing Stream
19. Entombed - Left Hand Path
20. Obituary - Cause Of Death
21. Carcass - Necroticism: Descanting The Insalubrious
22. Entombed - Clandestine
23. Bolt Thrower - The IVth Crusade
24. Amorphis - Tales From The Thousand Lakes
25. Darkthrone - A Blaze In The Northern Sky

Nice list