I also recently learned that Panda's can talk to a PyTable's HDF data storage on disk. This should be fairly seemless and can help reduce some memory issues with larger datasets. Yves Hilpisch did a nice talk on "Performance Python" that goes into this: http://hilpisch.com/YH_Performance_Python_Slides.html
Yes, I almost exclusively use pytables+HDF5 when I'm permitted. As I commented on some thread earlier this week, it strikes a great balance between simplicity, performance and flexibility.