How To: Making Linux More Secure
Some good points. I like the one that stated keep it lean and keep it mean.
I've not gone over my Linux install as much as my Windows boxes,.. and not done nearly enough on Windows, but I generally attempt to shut down anything I am able to that isn't needed on Windows. It's not a good way to judge things, but when I see a system running 100 or more processes, I wonder what is going on.