fresh install "best practises"?

[Robert P. J. Day]

   being relatively new to ubuntu, i'm wondering if there's a best  
practises list for what to do after a fresh install.  that is, a list  
of things people have learned over the ages to do as soon as a new  
system comes up that will prevent future recriminations along the  
lines of, "darn, i wish i'd done that right after installing."

   from my time on fedora, for instance, one of the first things i did  
was to enable yum caching of package updates, so if i installed  
another system, i had all the updates already downloaded (eh, disk  
space is cheap).

   another more recent example is that i'm playing with utilities like  
etckeeper that track all changes to /etc in your choice of a git or  
mercurial or bzr repository.

   anyway, you get the idea.  i'm not talking about what you read in  
the generic install manual.  i'm talking about tips and tricks folks  
have learned through (sometimes painful) experience.  thanks muchly.

rday