Another not mentioned much is Pericles. Creative and Phil he get's very fast libraries and thus extremely fast GS production. The UU has no early counter until HAs. The Odeon is pretty darned useful all the way through radio where it still get's additional bonus's for happiness (I don't remember which modern happiness wonder get's the bonus). Pericles is extremely strong in a spacerace or Culture game.
Pericles is also very strong for military games too. His UB makes the Construction beeline more tempting for early conflict. The Odeon is an absolute bargain at 40 hammers to assist growth whilst establishing culture, and may often justify a first build in a freshly conquered city. Cheap Libraries with Philosophical make it practical to accumulate gold whilst running scientists before getting a 75% with Academy bonus en route to Construction at around 1500bc. Pericles may lack a military trait, but fast Catapults combined with some stack defense will consistently give the AI serious grief on the offensive up to and including Immortal.
Philosophical has great synergy with Renaissance wars too with the old Philosophy, Education, Liberalism, Printing Press, Chemistry, Scientific Method bulbing path. Practically a dot map to State Property for some serious unit spam as you gradually transition your former GP farms into quality production cities.
Personally, I would probably rate Pericles the most versatile leader of the lot. Ability to rex combined with ability to research. Can effortlessly claim large continents with culture before backfilling, but can also make optimal use of minimal space via aggressive GP generation, which really just requires some food. No cheesy tactics or gambits required, just solid all around leader.
My only quibbles are the weak starting tech combination, and less than inspiring UU. The bonus against chariots is not enough to discourage me from building spears if mounted units are likely to be an issue. The free scout can be nice for extra gold and the ability to reveal further information on where to settle the capital. Unfortunately, Hunting and Fishing are not worker friendly on some maps.