Performance

I've read up some on performance tuning now that I have postgresql
running, and I'm wondering how I can make it run the fastest it possibly
can.  It's getting logged to by snort from 2 different firewalls, and is
getting approximately 200,000 inserts per day (this seems like a lot to
me but maybe not). and I'm wondering how I can tweak the postgresql.conf
(or anything else) to make the most of every cycle.

I've read that disabling fsync, setting buffer size, crontabbing vacuum,
and vacuum analyze, as well as raising the amount of time between
checkpoint runs helps.  I haven't read what I should set some of these
values to.  How high should buffer and cache size be? how high should I
raise the checkpoint?  Any other tips?

The machine is a Duron 933Mhz, with 256M RAM, with 2 40gb IDE drives on
a striped array running on OpenBSD.  The only other software running is
nagios, mrtg, and a couple of leetle perl scripts.

--Bryan