I'm totally with you. We've experienced to have Object database or XML database and NoSQL database. Now we understand that relational database is just the right way to go for web applications, because it deals with structured data so well, keeps querying and sorting, filtering seamlessly and effortlessly. It's a must.

It is the same thing for choosing Linux distribution and JDK mode. See the references here:

http://bingobo.info/blog/table-of-contents.jsp

BTW, your title should have "relational" instead of "relation".