mySQL or PostgreSQL?

I'm looking at using one or the other, but not sure about any advantages one
might have over the other. I've worked with RDBs in the past but am fairly
new to Linux. Any ideas? or pointers to GUIs for either?
--
Take care,
Jenny

Random quote of the day:
A musician, an artist, an architect:
    the man or woman who is not one of these is not a Christian.
        -- William Blake