Spoiler: Don't
You remember my other Minecraft post? A lot happened since then. Victor Engmark took my hack and made a nice tool out of it that runs way faster as well! Notch released the Halloween update with a new world that is at the moment called The Nether. And last but not least, I ported Mian to Clojure to form Clomian, to compare it to the Python version and to analyze The Nether.
There are still some issues with the code, and I might actually have found my first bug that is actually in Clojure and not in my code. Therefore I will talk and compare in another post, and for now just show you the results.
The bug:
(reduce #(map + %1 %2) (partition 5 (range 1e6)))
java.lang.StackOverflowError
(reduce #(pmap + %1 %2) (partition 5 (range 1e6)))
(99999500000 99999700000 99999900000 100000100000 100000300000)
The graphs:


As you can see The Nether is an unfriendly place with nothing but Bloodstone, Lava, Fire and Mushrooms.
Unlike the normal world, The Nether is 100% enclosed by Bedrock and in the middle, half of everything is still Bloodstone.
Unlike the normal world, there aren't any minerals and there isn't a clear distinction between above and below.
The only valuables I see are mushrooms and Lightstone, and these are somewhat uncommon and scattered across the whole level.
Conclusion:
The Nether is an interesting world, but it's not worth getting killed for, unless you desperately need any of those special blocks or shrooms.