System security. Antivirus complement or even replacement (for the bravest ;)).
I’ve never liked how so many software add themselves to be launched at system startup. And I’ve long had issues dealing with them (remember the time when msconfig, or even just regedit, were like the only options?). Then I finally found RegRun. It worked fine for a while, although with its fair share of issues (like system lock-down after uninstallation, hurray :/). But since I finally switched from Windows XP to Se7en, it’s been really unsatisfactory – it just seems quite broken on 7. And the support isn’t nearly as good as it used to be (seems like they locked their forums, notably).
Anyway, enough off topic, I eventually found a superior equivalent, with fewer features but at least they work and the ones missing were actually mostly unnecessary junk. This equivalent is WinPatrol. Its number one function is to monitor, every X minutes, what changed in Windows startup (ie, was a program or service added, removed, added as RunOnce?). Other more secondary functions include a quick access to all programs launched at startup, and all services, and configuring things to be launched at startup but after a specified delay, etc.
Of course, this can be used as a way to keep a clean system in terms of junkware. But since viruses usually add themselves at startup, it’s also a great complement to an antivirus software. Actually, my antivirus never caught a real virus while Regrun did catch a couple. Which brings me to the next level: you can (but don’t tell me I told you – the risks you take are your responsibility, not mine) also use it as a replacement for your antivirus. A must-have tool, in my opinion. And the free version is enough, although I think it’s worth buying the upgrade to support development of such a great, almost unique product.