Joe Celko's "SQL Programming Style" is a good not vendor-specific book.
As for PostgreSQL-specific books, I can only speak for one I read before: Bruce Momjian's "PostgreSQL: Introduction and Concepts". It is a good introductionary book, although it isn't based on PostgreSQL 8 series.
Unfortunately there isn't a current version of Joshua Drake's book out there (which I do own along with PostgreSQL Essential Reference by Stinson), so alternatively, can anyone recommend a good DBA book outlining best practices, physical design, etc? I would like something that is relevant to PostgreSQL even though it won't likely be PostgreSQL specific. Based on current best practices I could then investigate which tools postgres has available to implement them.
Currently our small company has a single redhat server for the database and web server, backups obviously are on a separate box. We want to add hardware over the next few months and would like to/need to separate functions and take advantage of things like: replication, PITR, clustering, failover, plgpsql, material view perhaps, and likely more which would be useful to speed up and protect our data.
I want to increase my DBA and postgres skills prior to the upgrade, and would like some direction from somewhere (book, group) on where to go from here. Our current database is about 50G large and is a fairly straightforward setup. I am the DBA and am also one of the developers, and my practical DBA knowledge comes from setting up our database and administering it. I make use of views and plpgsql, but from following the lists realize that there are many more tools available in postgres that could be used.
