Tried the FileHippo Update Checker a couple of years or so ago but wasn’t terribly impressed with it – as I recall it was pretty system intensive and also quite intrusive.

As a compromise, I’ve settled on the Secunia Personal Software Inspector (http://secunia.com/vulnerability_scanning/personal/) which I guess addresses the same outcome but from a different perspective: software which is vulnerable and/or outdated.

It doesn’t automate the software downloads at all for you, but overall I found it a happy compromise. Most of the home sites I “support” have it installed.