Best database for a server. (Generally, not only Conquer)

When I refer to 'database' I mean 'flat-file/MySQL/MsSQL/PgSQL/MariaDB/etc'.
So, what's the best database for a server? Come with valid arguments please(tested if you can).

I myself tend to think that a good choice is MySQL.
Why? Well, it's probably a bit slower than flat-file, but you don't have to parse the data as it comes. But, it gives you the chance to have a connection with the website and show information about a character linked to an account and so.


#For mods. - No, this kind of thread wasn't created here. Or atleast I didn't see one for the past few years I've been here(I had another account).

I would say MSSQL, because the biggest Pizza/Resturant site here in Denmark is using that and they have like thousands of connections all the time. The site is never down or slow. The reason I know it, that's because one of the one who worked for them and coded it has been our teacher and he knows quiet a lot about it. It's ASP.NET thought using C#. I would say it's MSSQL for that reason he knows wtf he's talking about.

I have always been a fan of flat file databases.
I find it much easier then other databases but i do think MySql would be my second choice i'm giving this a bump hoping it sparks something up i'd love to learn about different database =o

I prefer MySql or Oracle.
The PL/Sql for Oracle is pretty awesome, and MySql is free and easy and awesome.

MAN UP
Write your own!

I use MsSQL at work, and MySQL at home, i have used PgSQL and found it to be horrible and inefficient, forget about flatfile, its just an under optimised version of any other database you can think of.