@Codeman: why do you need a website? Is this for a school project or something? (There’s nothing wrong with that; I’m just trying to understand your requirements.)
Most people, I’d guess, start from having a business, leisure group or project and build the website from there, because they need it, rather than wanting a website and then looking for a subject.
The coding of the site can be as simple or as complex as you choose to make it, but you also need to be able to provide enough content for your project. Unless you propose to pay a content writer, then as @Gandalf says, you need to pick a subject you are interested in and know something about.