Well, I just wanted to use pandas to load a 4GB csv file. After using 32GB of my RAM, and 4GB of swap I gave up. I've just loaded all that data to Postgres, and made a couple of queries. This way I stopped using pandas at all.
After that I usually just keep the numpy array since all I need is floats. I guess the index groupby stuff is cool, but I never really needed it. Postgres is fine but if you're just doing numerics it doesn't help much.