It really depends. I think making it natural would be better. Lots of people use a bunch of paths and PWPs to make their towns themed, which is fine, but I'd like to see natural beauty. Maybe make it look like a real town, with parks, streets, camping, houses, etc.
Like I said, this is all your idea. You could definitely make it based on a season, holiday, show, or whatever.
I'm thinking I might do a pastel theme. Lots of flowers, maybe some bright paths. All these ideas sound lovely. I might have to incorporate more than one idea into town