...as in Life, (en-Kor + Spiritualist + Condemn/Diamond Valley) Death, (en-Kor + Spiritualist + Doran, the Siege Tower) and Everything In-Between.

Life.dec has always been a favorite of mine. I played it back in old Extended using About Face and Dwarven Thaumaturgist as kill conditions. I've toyed around with various incarnations since, and this is the best one I've come up with.

The purpose of the deck is to gain billions of life and/or swing for billions of damage. Pretty self explanatory. For those who don't know, this requires you to target a Daru Spiritualist or Task Force billions of times with a en-Kor creature and then use Condemn or Diamond Valley to gain billions of life, or Doran, the Seige Tower to attack for billions of damage.

The list:

Mana - 20

4 Scrubland
4 Bayou
4 Flooded Strand
4 Windswept Heath
2 Plains
1 Forest
1 Temple Garden

The Combo - 14

4 Nomads en-Kor
3 Shaman en-Kor
3 Daru Spiritualist
4 Task Force

Life - 3

3 Condemn

Death - 3

3 Doran, the Seige Tower

Tutors - 7

4 Living Wish
3 Eladamri's Call

Everything In-Between - 13

4 Tarmogoyf
4 Swords to Plowshares
4 Thoughtseize
1 Mother of Runes

Sideboard:
1 Shaman en-Kor
1 Daru Spiritualist
1 Doran, the Seige Tower
1 Harmonic Sliver
1 Serra Avatar
1 Diamond Valley
1 City of Brass
1 Volrath's Stronghold
2 Vexing Shusher
3 Krosan Grip
2 Sylvan Safekeeper

Card Choices:

Condemn: Combo piece that doubles as creature removal.

Tarmogoyf: Best creature in the format, it can occasionally win games on its own. Gets better with Doran.

Thoughtseize: Combo protection. Every deck with black in it has no excuse for not running at least three.

Mother of Runes: Protects combo pieces and can help you swing for the kill.

Harmonic Sliver: Wish target to get around Counterbalance, Chalice, etc. Can also potentially be recurred with Diamond Valley and Volrath's Stronghold

Vexing Shusher: For Counterbalance, FoW, etc.

Krosan Grip: For Counterbalance, Engineered Explosives, Pernicious Deed, Phyrexian Dreadnaught, etc.

Sylvan Safekeeper: To protect vs creature removal. It's kind of a lame choice, but I couldn't think of anything better to do its job.

Matchups:

I haven't really tested this much. It seems very strong against aggro, okay against aggro control, poor vs board control, and terrible vs combo.

Questions for discussion:

Should more slots be dedicated to the life combo, i.e. run Worthy Cause and more cards to sacrifice creatures for life?

Dark Confidant, hot or not?

Can the sideboard be improved? The sideboard I built is for my metagame, which has little combo and next to no graveyard dependent deck like Ichorid, Loam, and Breakfast. Perhaps someone could suggest a more general sideboard.

Is there a better card than Sylvan Safekeeper?

Is the aggro backup plan worth the slots?

Spirit en-Kor and Angelic Protector to dodge Counterbalance?