AfterShafter
Deity
Really? Wow, AfterShafter, I thought you used to slam the fast worker in older threads circa '06
I did? I was a huge Gandhi fan in '05/'06

Anyways, Fast Worker gets my vote for one major reason now - I'm playing on Deity, and when I attack is dictated almost entirely by proper window of opportunity, not by when I get my super-cool unit. If my empire isn't ready to wage one of those arduous Deity wars with swordsmen, Praets aren't going to change that. Nor Oromos or Cataphracts or Redcoats in their respective eras...
Thus, Fast Worker gets my vote - he's always helpful to me, whether I'm going to war or not. What wins me games in Deity is being able to get my empire running ASAP, and being in as stable a position as possible in a really short time frame before I go to war. Fast workers always help me with that.
My vote goes for cataphract since my #1 pick is off the list... Red Coats getting a secondary nod. They're sometimes useful in their eras as I'm playing now, whereas things like War Chariots and Quechas get me killed 9/10 times, so what bloody good are they? Praets... Meh, most often I'm not ready to go to war at the point they're really useful. What's more, I just find them overrated at anything other than exploiting weak AI's these days.