Just my 2 euro-cents in this very interesting thread. I saw Coriolis effect mentioned. You can forget it. Coriolis effect is millions times weaker than forces, pressures and velocities at work in our systems.
The common idea of water spinning down the drain because of Coriolis effect is a total myth. Spinning (swirls, etc) is provoked by fluid motion if it's already moving, or assymetry / irregularities of containing surfaces.
More details ? Read this:
http://www.ems.psu.edu/~fraser/Bad/BadCoriolis.html
Now back to our regular scheduled program