Reasonable Configuration

Hi,
the postgres configuration file is somewhat confusing to me and I could
not find a good tutorial on how to configure the db.

I have a single and dual processor machine, 1GB of memory.
The database is a couple of GB, about 10Million records.
The system runs batch jobs that can be quite heave. Users connect via
Tomcat.

What would be reasonable figures for

- shared_buffers
- wall_buffere3s
- sort_mem
- vacuum_mem
- effective_chachesize

these are the ones that come into my mind.

I have allocated 512MB of the system memory to shmmax and shmall


Are there other parameters of the default config that need attention ?

Thanks
Alex