Oracle-style table partitioning
Tomasz Nowak commented
Yes, it is must have for PostgreSQL as even MySQL have it already.
There is a kind of partitioning in PG (inheritance), but the implementation is not very elegant and with many limitations.
must have in billions rows tables world
This has been started and has several useful components to full solutions here built already: http://wiki.postgresql.org/wiki/Table_partitioning