Seaborn is great for visualization; it basically packages up some of the more specialized R plots for MPL. The other thing I really love about it are plotting contexts, which make it really easy to properly size and format the same plot for e.g. a poster and a paper.<p>Interestingly enough, my biggest use of Pandas is to serialize to and from HDF5. I work with a lot of large datasets and Pandas simplifies using HDF5 quite a lot.