I voted for
Fall of Rome. I loved the Barbarism tech tree and the Warlord branch of units. The array of civs to deal with is good. I live in Britain also, so playing as the Celts and kicking the Romans out was sweet! This scenario's excitement level also keeps going up to the end due to having to dispatch both Eastern and Western Rome.
This is quite unlike
Rise of Rome which I found a repetitive, constant warring slog (both as Persians and Greeks) against the same few cities until you finally break through, then do the same for the next city till the 66%s show up. There was no diversity in that one just war.
I would have voted for
Sengoku but the damn ninjas were bugged. Grrrrrrrrrrrrrrrrrrrrrrr. That made me so mad. This was a brilliant scenario - new units are great, love the historical accuracy (in places), the tech tree is well conceived IMO. Generally this was a good challenge. But they ruined it! Was this fixed with 1.22?
The
Napoleonic Conquest as Britain is an absolute blast. Now that's naval power!!! So many enslaved ships. Russia would be a goody to play too.
Middle Ages is fun but, however authentic the challenge of taking Jerusalem is, it is a little contrived or should I say it's an unusual victory condition. I played this one as the Swedes and after bashing up a few other civs I smashed my way in Jerusalem from my Cypriot barrack town.

This was fun! I also played this as the Turks and found it much more difficult. Those Bulgars and Magyars do expand right across and they're pretty unfriendly.
Age of Discovery is from one my favourite periods of history and it was great to see the balance between Catholicism and Protestantism being address and also the importance of banking and the printing press in this era. And at last Firaxis drops the PC attitute and includes some good old Slavery! I can't belive they ignored this major factor in world history for so long. This was a colourful scenario to play if a little easy. I'm gonna crank it up in difficulty level and have another go.
Meso was so so but I aint much of a wonder builder.
Haven't played the Americas or WW2 ones yet and any others I haven't mentioned.
BTW - No one can complain that a scenario is too easy - bump the levels to get to the heart of each conquest.