Lockdown is an insane anti-theft system for Mac (specifically laptops) that is very customizable to your specific needs. For example, you can set it to set off its alarm from the internal motion sensor, mouse movement, keyboard input, removal of your MagSafe power cord, the lid closing, or any connections from external devices. When the alarm is triggered, it can make your iSight camera take a picture of the perpetrator, and automatically email it to you. You can arm or disarm Lockdown with either your Apple Remote (which is specifically paired with Lockdown itself, so no others work with it), or with a password supplied via the keyboard. You can even force it to crank up your volume all the way when the alarm goes off. It has tons of options to help keep your laptop from being stolen, which is extremely useful in public places like on campus, or at the coffee shop. I very highly recommend this app for any owners of Macbooks or other Mac laptops.

Rating: 5/5. Great HUD interface, awesome functionality.

Developer site:
FoozooDesign.com/Lockdown.html

Locker is an extremely simple app that lets you lock or unlock files or folders. It works as advertised, and is dead simple. It also supports batch locking/unlocking. Keep in mind that locked folders or files can still be opened, just not modified. While you can do this from the Get Info pane, Locker is easier and more intuitive.

Rating: 4.5/5. A contextual menu item for this would be appreciated, but it works all the same.

Developer site:
VojouSoftware.com/Locker

Pastor is an old Mac freeware favorite of many.  It’s a very simple password management system, and a place to keep any private information you want. It also has a great password generator, and some other nice little features. It’s essentially like the ultra-popular 1Password, but free, and just a little bit watered-down. Still an awesome app, though.

Rating: 4.5/5. I like the simplicity, but some better integration with other apps would be appreciated.
 
Developer site:
Mehlau.net/Pastor

Now, having posted about the risk of patching the ARDAgent exploit, it seems like this would be an unlikely post for me to make right afterward. But, if you are so inclined to patch it for fear of getting a trojan, ARD Patcher is a very safe technique to do it that was developed by a friend of mine. Having tested the beta version for him, I can assure that it does not cause any damage, and is completely reversible. ARD Patcher is a dead easy, secure way to patch the exploit. As an added bonus, it comes with the source code!

Rating: 5/5. Awesome, it’s always nice to feel safe (and get back at all the Microsoft nerds who thought Macs had a virus).

Developer site:
TheiPhoneProject.org

Believe it or not, every recently made hard drive has a built-in SMART chip, which can predetermine hard drive failure before it happens. The problem is that no operating systems read this SMART chip’s information by default, so it’s essentially useless to most people. But, with SMARTReporter, you can interpret the information it has with ease. SMARTReporter sits in the menu bar, and shows a little (changeable) hard drive icon. By default, a green icon means everything is working fine, a gray icon means the status is unknown, and a red icon means your drive is at risk of failing. With this information available, you can know to back up all of your files before your hard drive dies.

Rating: 5/5. Awesome, very useful. Could just save your bacon someday.

Developer site:
CoreCode.at/SMARTReporter

WaterRoof is a powerful firewall tool that can let you change a lot of OS X’s firewall settings.  Normally, these settings can’t be found through a GUI, but WaterRoof bridges that gap.  You can set bandwidth limits, and do tons of useful operations that can help keep your Mac safer.
If you’re intimidated by the vast amount of settings in WaterRoof, you can try the watered-down (no pun intended) version, called NoobProof. NoobProof consists of five easy steps that walk you through setting up your firewall.

Rating: 5/5 for both apps. One is easy, one is advanced. Both are excellent.

Developer site:
HanyNet.com/WaterRoof
HanyNet.com/NoobProof