So I am researching the culture changes which might become important:
Culture bomb value is now 800*era, i.e. classical age ->1600, middle ages -> 2400, renaissance -> 3200, industrial -> 4000, etc.
Cathedrals give only +40% culture
Colosseum gives +20% culture
"many buildings" give less culture
Free speech only +50% culture
1000 year bonus only doubles base culture, without Sistine bonus (e.g., 1*2+3 instead of (1+3)*2 for temples).
Hmm... 300H GLighthouse... reward with 8 coastal cities are 16 trade routes with, let's say, a value of roughly 3 commerce, i.e. 54 commerce per turn. So it pays for itself at 1H=3C in roughly 20 turns. Still a good ROI in my book, and opportunity costs are not that high in my case.
Let's just hope nobody else builds it first...
[edit]
Turn 101. Build the GLH, settled three more cities, including the island city (which gave me immediate +16 beakers - noticeable when you jump from 83 to 99). Research has resumed - with 1300 gold in the bank, and at -24 per turn I can keep 100% up for a long, long time. First GS is imminent, which will build an academy at Nottingham, which will become my capital in some time as well. Research has resumed, and after a brief diversion for agriculture, maths has been researched and currency is next. Then probably metal casting for colossus, and monarchy for happiness. Settling the last spots, horse/fish, 2S of wheat and on the marble is my next goal - actually, that should have already happened, building a lighthouse/library in York was probably a mistake.
State of the land:
So... should I head for culture or not? Christianity is already taken by now, btw.
I got it a bit later, along with Engineering in 800 AD. I'd be interested to see your save and to hear what what was your strategy.
That GA would have been very helpful. Tech path was very, very sloppy as well. Several stupid mistakes - switching into caste when I could run no specialists, etc. Got Astro in ... 1000 AD or so 
Trying for music also delayed much-needed Monarchy, etc. 
