There's no need to do any of that for most home users. And doing security by obscurity is one of the best ways of opening yourself up for attack (referring to your linux comment)
Burnsy
I don't really see how it's security through obscurity. if anything it's the opposite, the basis of that theory is that those using the system are unaware (and possibly deliberatly kept that way) of the systems security and consequent vulnerabilities, whereby with Linux it's usually the user is the limiting factor. However i don't see a huge benefit from a firewall point of view when using Linux since most people can't be bothered to setup iptables or even enable it (and some distros aren't even that secure out of the box anymore).
From a malicious file point of view i can see a benefit (less so with Vista than XP) as you'd need executable rights to run anything which is a conscious step in giving it.