That windmill is my favourite one. I think the different sections need to be fairly large. No point having only 3 buildings in the same style.
Here are some architectural designs I've thought of implementing.
1) Medieval
2) Roman (near the Arena)
3) Greek
4) Nordic (Skyrim-esque buildings)
For the texture packs, I don't use any since I'm very nit-picky about certain details.
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