If you purchase a lot of apps outside of the Mac App Store, keeping track of all the serial numbers or other related info, like the developer’s website, can be a pain. AppShelf ($9.99) can keep track of all of this for you. You can fill in much data as you need and best of all, you can password protect the program, avoiding prying eyes from “borrowing” those precious serial numbers.

What could be a better Desktop wallpaper than the entire world? This is what Blue Planet ($4.99) offers. Instead of a still image, you see the day and night zones slowly changing over time. You have a choice of four maps, and you can center them on your location or have the map move gradually. You can even jump forward or backward in time. Sadly, it doesn’t offer a cloud cover option.

Setting up multiple clocks in your Dashboard isn’t that convenient because if you have a lot of widgets open it takes a few seconds for them to update. So Clocks ($1.99) is fantastic if you need to know what time it is elsewhere in the world. It’s accessible from the menu bar, and best of all, it has a slider to make sure that phone meeting you’ve agreed to won’t be in the middle of the night!

If you want to know how your Mac’s processors are faring, you could always open the Activity Monitor in your Utilities folder. Problem is, there’s a lot of information there that can be overwhelming to novices. Thankfully, CPU LED is a free program that simplifies all this by giving you a small colored icon in your menu bar. CPU LED even lets you choose a design for that icon, from a hefty selection.

If you're in need of a graphing calculator, don't let the "Lite" in Graphing Calculator Lite ($9.99) fool you. It's a powerful tool that can produce graphs from complex formulas. If you’ve created a three-dimensional shape, you can even rotate it to see it from a different angle. There are some things it can’t handle, though, like tables, vector operations, and differential equations.

You’re used to sliding your iPhone to unlock it, so why not do the same on your Mac? Lock Screen 2 ($1.99) requires you to disable your Mac’s usual password protection, but then, one quick keyboard combo (Command-L) activates the lock screen. Slide your finger along the keyboard or trackpad to unlock, or set a pattern to follow to unlock the screen, so no one but you can access your Mac.

The free Mactracker is an encyclopedia of every piece of hardware Apple ever created, even long-discontinued printers, cameras and even the venerable Newtons. Everything is there, which means that if you ever need to know any kind of information about a particular product, say, to confirm the type of RAM you need to upgrade your machine, Mactracker will be able to tell you in seconds.

You may be able to search the web straight from Spotlight, but it’s not as convenient as the 99-cent MenuSearch, which puts a search box on your menu bar that you can access anytime with a convenient keyboard shortcut. You can also choose the search engine and even look access Wikipedia straight from that field. The customization options in the preferences help you make the app your own.

To control your Mac from across the room, get Remote Mouse. The Mac app is free but you also need one for iPhone ($1.99, shown) or iPad ($2.99). Connect via Wi-Fi, then control your cursor, scroll around, and even type.

Rulers ($4.99) can turn your entire screen (or all the screens connected to your Mac) into a design area, just like in Photoshop. You can set up rulers, add as many guides as you need, and check the size of specific areas, which can be crucial when designing interfaces, for instance. You can also use those guides to define a specific zone for a screenshot of -- a lot more precise than Shift-Command-4.