Name: The Ash Pits
description:
a lager cavern with massive deposits of almost black brimstone, some burning with blue fire, and a constant snow of dark grey ash pouring down from the ceiling and on the ash filled soil a ember bloom flower grows giving off a faint light
top soil:
mostly brimstone and dirt with a covering of ash
New blocks and items
brimstone- burns like netherack, except the fire is blue, can be crafted with 4 charcoal and 4 bonemeal to make 16 gunpowder
ash- like snow only grey yields 3 to 4 ash piles when mined, can be used as fertilizer or fuel
ember bloom flower- can be harvested by hand or shears, however harvesting it by hand will set you on fire. yields 3-5 blaze powder when crafted can be grown by using ash as fertilizer on dirt next to lava

Name: the Ember marsh
description:
like a swamp only with lava instead of water. and gravel and hot coals instead of dirt the trees are made of charred wood (no leaves)
New blocks and items
charred wood - yields 4-6 charcoal when mined (only obtainable with silk touch)
hot coals block - damage mobs that touch them

Name: hell dessert
description like an ordinary desert only with gravel, charred dead shrub, and red-orange Infernium crystals instead of cactus
New blocks and items
charred dead shrub - yields 2-4 charcoal when mined (only obtainable with silk touch)
Infernium crystals - yields 2-4 infernium shards when mined (only obtainable with silk touch), light mobs on fire that touch it( can be grown by planting the shards in gravel)
infernium shards - used as a fuel or used to craft infernuim tools/swords (basically stone tools with fire aspect and a different texture)

This would be very cool I think. I would only suggest the inclusion of netherrack into the biomes, since it is the nether!

I'm not into the Nether at all...and avoid it at all costs. The ugliness there is not something I enjoy, plus there are really no living plants/trees...etc. Others will have to come up with ideas for it...because if it was left up to me...the Nether and anything like it would be removed from the game...lol :P

well I thought that netherack was the stone of the nether
and honestly I've never liked the barrenness of the nether either

Well, lets make sure we're keeping things straight.

There are world types -- mostly flat with hills, or giant caverns, or flat, or islands in the sky, etc.

Within those world types, there's types of landscapes and creatures.

Giant caverns that look like hot lava spots in some places, frozen ice balls in other places, and brimstone, fire, and ash in other places: Why not?

Mystcraft lets you have "hell biomes", where nether mobs spawn, but you still have normal ground. Or, you can have cavern worlds, with any biome. Or, you can have the world with netherrack instead of stone.

If the goal is to add variety to the standard nether, then I'm all for that.
But lets keep clear what's a biome concept, what's a ground "stone base", and what's a world topology.

Now, we've got something new with Terrain Control in EBXL 4. I had asked Scott if it was possible to generate chunks using the nether generator to make a cave, and put a "border hill" around it so that someone on the outside sees a giant hill that goes up to 128 and then becomes flat, and he confirmed that this can be done, and has already been done. So we can have something where a world has a mix of plains, forests, and ... something strange where there is ash, brimstone, and lava hiding inside a ginormous cavern with grass on top of it.

That's a type of world that minecraft has not seen yet.

"Nether Marsh" could easily be a case of "Deep around Y=12, at the lava lake, we have a different set of rules for the decorations". So deep down, near the lava, we have swamp-like conditions; up on the ledges above, it looks more like the normal nether. But that gives a new concept in decorations -- that instead of only one rule for "how to decorate the tops of any ground area" that affects all "under overhangs", you now have different rules for different layers/levels; note that the hell desert implies a special set of decorations for the mid-levels (near the 64 line). Which will make for a seriously fun attempt to define, in code, based on overhang layers.

While we may not be adding biomes to the Nether, some of the mods we have inherited do add some things to it, that we may add in a future release.

Thank you for your suggestions.