That depends on your taste. In my opinion the vanilla game can be fairly enjoyable, but I like to tinker with it nonetheless to suit it to my preference.

A lot of people do the same, but also release their mods to the public (which I don't do because I don't think there'd be too much interest in my personal style ). You can find most of them in the Mods in Development section.
To find something that you like, I'd first try the game as it comes out of the box and then try out some mods so that you're able to compare.