New server configuration

I've got a new server which I'm looking for some assistance on
determining the best configuration for PostgreSQL. It's the first time
I've had to set up a new PG server from scratch and it has very
different specs to our other servers which I don't think were properly
tuned anyway.

The basic server specs are as follows:
CPU: Pentium Xeon Quad-core 1.6GHz
RAM: 4Gb 633MHz DDR
HDD: 6*146Gb SAS drives in 3*146GB RAID-1 sets.

The database will have one process running that collects data from
various external sources and pipes it into the database via a single
connection. These udpates can be as few as one every couple of minutes
or as many as 50-100 per second depending on the time of day.

A number of users will connect at various times of day with a reporting
tool such as Microsoft Access, Crystal Reports, and some of our own
in-house things pulling at times large chunks of data out, at other
times smaller chunks.

The server will be dedicated to running PostgreSQL with a few smaller
apps that take up next to no CPU/Memory/Disk.

At the moment I've got the disks arranged with 1 for software, 1 for
data and 1 for transaction logs/WAL.

I'm curious to know what some might suggest are the best settings for
resource usage (shared buffers, maintenance_work_mem etc) WAL and
autovacuum - I can dedicate basically as much of the system resources to
PG as it would need for best performance.

TIA,

P.

--
Paul Lambert
Database Administrator
AutoLedgers - A Reynolds & Reynolds Company