Working with Dates between MySQL / PHP

What’s your favorite way to work with dates when passing them between PHP / MySQL? At some point between the db and output (for most situations) you’ve got to convert the formatting of the date from whatever is in the db to whatever will be displayed.

So, do you use the native MySQL field types such as DATE, TIME, DATETIME, TIMESTAMP, etc., or do you store it directly as a Unix time-stamp via another filed type?

(This is more a discussion / curiosity thread, btw…)