I wasn't trying to start a flamewar! I'm just coding up my first major project and needed help deciding, specifically which one plays better with django.
If you're using Django, and all else being equal, I'd choose PostgreSQL. Nearly all of the core developers (myself included) use PostgreSQL, so Django tends to have better support and we tend to find (and fix) PostgreSQL-related bugs a little bit quicker.
That said, plenty Django sites use MySQL -- including some of the very biggest ones -- without issues. So you're really in good shape either way.