The HTTPServer object is very close to the HTTP protocol. While this is powerful in the same way that driving a stick shift car gives you low-level control over the driving experience, typical web application programming is better done at a higher level. Does anybody use assembly language to write web applications? It's better to abstract away the HTTP details and concentrate on your application.
The Node.js developer community has developed quite a few application frameworks to help with different aspects of abstracting away HTTP protocol details. Of them, Express is the most popular, and Koa (http://koajs.com/) should be considered because it was developed by the same team and has fully integrated support for async functions.
The ExpressJS Wiki has a list of frameworks built on top of ExpressJS, or tools that work with it. This includes...