partition question for new server setup

I have the opportunity to set up a new postgres server for our
production database. I've read several times in various postgres
lists about the importance of separating logs from the actual database
data to avoid disk contention.

Can someone suggest a typical partitioning scheme for a postgres server?

My initial thought was to create /var/lib/postgresql as a partition on
a separate set of disks.

However, I can see that the xlog files will be stored here as well:
http://www.postgresql.org/docs/8.3/interactive/storage-file-layout.html

Should the xlog files be stored on a separate partition to improve performance?

Any suggestions would be very helpful. Or if there is a document that
lays out some best practices for server setup, that would be great.

The database usage will be read heavy (financial data) with batch
writes occurring overnight and occassionally during the day.

server information:
Dell PowerEdge 2970, 8 core Opteron 2384
6 1TB hard drives with a PERC 6i
64GB of ram

We will be running Ubuntu 9.04.

Thanks in advance,
Whit