hmmm, are you sure you got gentoo and not debian sarge stable.
Anyway do a
netstat -ap
and see what servers are running. See what you can remove and what you want to keep.
if it is gentoo do and emerge sync and then an emerge -upv world and it will show updates for your system.
if it is debian do and apt-get update and apt-get upgrade to install updates for your system.
If you have time and guts go to
www.grsecurity.com and get their kernel patch. This will get you something to do for a while. Getting the kernel correctly tuned to your system.