ErisDS, I've only just become aware of the kind mention of some blog posts I wrote on this. My own working approach is based on the view that some hackers are incredibly good so if they really want to attack your blog they can probably find a way. Therefore you should make sure that your blog is as strong as it can be so that hackers will go and attack other blogs that are not so well protected. There are hordes of insecure blogs out there, some with significant traffic, so any smart hacker can find what he or she wants.
Having said that, I think it's important to:
a ) Make database and blog backups on a regular basis
b ) Always upgrade to the latest version of WordPress so that you're protected for any vulnerabilities that may have been found.
c ) Be extremely vigilant particularly during weekends and statutory holidays, when some of these attacks seem to take place. That means checking the source code to make sure no malware code has somehow been added.
There are more specific hardening tips that are given in what Matt Cutts and I wrote and those are useful too.