Best format to save date?

[eluser]xwero[/eluser]
nOxie database experts say it's better to leave the formating and manipulating up to the programming languages to make the database retrieval as fast as possible.
But if you use caching the database speed becomes less important. And why do all the database products have a date datatype if they suggest to use an integer datatype?

I guess there will always be two camps and many ways to do what you want.