Performance Tuning Best Practices for 8

I've been using postgres off and on since about 1997/98. While I have
my personal theories about tuning, I like to make sure I stay
current. I am about to start a rather thorough, application specific
evaluation of postgresql 8, running on a Linux server (most likely
the newly release Debian Stable).

While I have been running 7.4.x for a while, I have not had much of
an opportunity to really look at 8. Are there any significant
differences or gotchas tuning 8 as compared to 7.4 or older versions?

I was hoping those that have 8 in production environments might share
some of their tuning experiences with me, or point me to useful web
sites or books. Most of the websites and books I've seen on this
topic are from 2003 and 2004, so I was hoping to find something a
little more current.

Thanks,
Greg