20% wonder building bonus is huge... Basically allows me to build any wonder. If not every wonder.
And burial tombs gives 2 culture 2 happiness. Bad UU that I never use. If I want to spam wonders no one comes close to Egypt. And since this is Civ, I definitely feel like spamming wonders very often. I'd probably put them #1 for cultural victory potential.
I usually play on Emperor-Deity. On Deity warmongering is the easiest strategy so I like the Aztecs.
Also religion is a gimmicky joke and very hard to get on deity with not so many benefits. I have 22 opponents on going for religion so I really don't focus religion. It's not worth it unless I'm making religion my core strategy, in which case I'd use Byzantium. I'd say that building Pagodas and Mosques is the best effect of religion. Then the "Just war" makes is sort of worth it. You can also add that 34% spread speed as a bonus.
As for the best civ I have to say Aztecs. It's impossible to lose as the Aztecs. I rape all the computers every time and I don't even really need peace... ever. This is deity I'm talking about here.
It's really a joke how good the Aztecs are. I'm always at war and I just leech massive amounts of culture. I get the honor policy tree as soon as I can which is easy and takes almost no time. Then I get gold for all my kills as well as culture.
So right there... In one fell swoop all my economic and cultural issues gone. My only probably is I don't have enough enemies to kill and all the comps annoy the out of me begging me for peace every turn.
Basically the jaguar warriors are the first unit you get, easily spammable, moves easily through forests/jungles, and here is the kicker +25 hp after winning a battle. This upgrade stays through-out the game. So I spam jaguar warriors and just have an epic army which I upgrade at a 33% discount.
Since I'm always at war I don't really care about diplomacy and I make agreements I never honor. So I rob the computers every chance I get diplomatically. (Easy money)
So I basically the Aztecs have no comparison as far as I observed.
I can see how other civs can be better war-mongers like the mongols and the huns but they don't have the economy backing them up like the Aztecs. The Aztec special building give ridunculous (ridiculous) food bonuses which makes it GG. After my war mongering is done and my core cities are set up, I usually have the #1 spot.
Basically a typical game is over after the classical/medieval era when I rush and enemy capital with 4 jaguar warriors + 2-3 archers. I get two good cities fairly fast. I'm stealing workers the whole time while producing my military. I fall behind tech/economy but I quickly catch up as I have more cities/resources. And everyone around me is my feeding my culture.
No one has given me better results or comes close. My only complaint about the Aztecs is the lack or wonders and religion. Which is why I play Egypt/Byzantium. I really want to try the Arabs now after reading this thread, I never thought about their money making potential.
So my top civs:
Cultural - Egypt
War Mongering - Aztec
Religion - Byzantium - Only civ really viable with religion because of the bonus. I also really enjoyed their special units which are both monsters. I ripped everyone apart in my current immortal game and I'm getting like 100 faith a turn converting everyone
Civs I assume are really good:
Persia (Surprised I still haven't played them yet, guess I'm enjoying Egypt too much since they get everything... 150% golden ages? YES PLEASE.)
Mayans (Shrines give 2 science and faith? lol! Free great people? ROFL)
Carthage (Free harbor? Holy ...)
Huns (Battering Rams? Free husbandry and hammers? Holy crap...)
Arabia (Very well rounded, I want to try them)
Austria (Broken ability at the moment, but I still don't like them.)