How to optimize search through 1 Terabyte in PostgreSQL

Today I wanted to share my experience of using a relatively big database. It's an active running database containing near 1 TB of data managed by RDBMS PostgreSQL 9.0. The most significant part of the data is located in only 2 tables, 650 GB and 350 GB respectively. There are lots of queries populating into these tables - nearly 15-20 inserts per second, however there are just few selects per minute. Each row in either table contains up to 50 KB of data. Additionally there is a single cleaning query starting once a day in order to remove oldest data and prevent excessive database growing. Well, let's take a look under the hood.

Awaiting of PostgreSQL 9.1 - short features review

Few weeks ago a PostgreSQL team announced the first release candidate of their powerful DBMS. It means that the release is going to be ready in several months. In the published release notes they have written following interesting information:

This release shows PostgreSQL moving beyond the traditional relational-database feature set with new, ground-breaking functionality that is unique to PostgreSQL.

From my point of view this is not just marketing words because every PostgreSQL major release always contained really  significant changes, which gives us high expectations for future releases as well. So, what are real advantages we might get from version 9.1 once it's released?