When you download a new application, its installation process typically tells you to either drag it into your
Mac's Applications folder, or it has a full-blown installer that takes care of this process for you. But who says you
have to keep all your apps in the Applications folder? Many applications, from Firefox to Quicksilver and even FCP and
Photoshop, can generally be run from nearly any folder on your Mac, allowing you to organize your applications any way
you see fit.
Why would this matter, you ask? Well, if you're anything like me, you've built up a healthy collection of 3rd party apps that you use on a regular basis. If you want an easy way to either backup all these apps or quickly bring them all over to another Mac, you can simply keep them in a folder in your Home folder. This way, you can still use them and call them with tools like Quicksilver, OS X can still find them, and you can easily keep track of just your apps that matter most. This also saves a lot of time if you ever decide to do some serious "spring cleaning" and wipe your entire Mac.
Now, one word of caution with this tip: as a general rule, exercise care when moving around any of the big apps, as well as the apps that used a full-blown installer. I had no troubles moving the entire Photoshop CS2 folder and Final Cut Pro.app to my desktop and running them, but I have no idea if a move like that could affect the functionality of things like plugins or other addons. My personal rule of thumb (which hasn't failed me yet) is that if an app is a simple drag and drop install, it doesn't necessarily have to live in the main Applications folder.
If you've been using a similar trick like this, TUAW readers, feel free to discuss your ideas in the comments.