Mine:

Charm+Bead+Biscuit+2 wards+ HP pot (wait in base for ~10 seconds after minion spawn for the pot)
Philo + Flask
Sightstone, Emblem of Valor, and Boots (been going Emblem first most often)
Aegis
Boots 2 (Mobility, Tabi, or Mercs)
Kindlegem
Spirit Visage
Crucible (take before SV if facing heavy cc like WW's suppresion or Amumu's ult, for example)

Upgrade Aegis to Bulwark at some point in there if AoE magic damage is an issue (or there's just a really fed ap carry). Also, tried getting an Iron Solari Locket before Crucible in a game where AoE was being a big problem in general (won the game, but not sure if this is optimal).

Has anyone else done any experimenting?

Char+pots+wards
philo
sightstone/boots
boots/sightstone
upgrade boots
upgrade sightstone
rush aegis
rush bulwark

build situational items.

A delicious biscuit and some sodas so you don't get thirsty, followed by a pair nice shoes and a few pretty rubies.

6 stacks of health pots

rush black cleaver and then fill the rest of your inventory with wards.

6 item opening

philo

aegis because sightstone is a noob trap

situational support items

Dyrus approves of 13 Hp pots.

BC
BC
BC
BC
LW
whatever boots you want