This is one of my favorites, you select the source (either a DVD you own or a movie you created by some other means) and you convert it to an iPhone/PC/Mac/iPad/Xbox360/Roku compatible file and enjoy! Sure, it does take quite a bit of time to convert, but for a guy like me who likes to keep the computer on for long periods of time, this definitively rocks.
I have seen little groups that enjoy their work as much as MacPaw does. They have great no-non-sense apps, competitive prices, and promotions run on their twitter account. I have Clean My Mac on every Mac computer I own. If you want a discount on the 2-license pack just let me know! (No, I do not get paid to publish this, but I really really love their software)
If you have an AppleTV and you want to EXTEND your desktop onto it (wheter you have a PC or a MAC does not matter), this app is for you! At an unbeatable $9.99USD price tag it is so cheap it may as well be free! I highly recommend it, try it out if you do not believe me! Supports Audio and Video. Way better than Apple's own AirPlay for Mountain Lion.
I tried 3, Avidemux did not run on any of the Macs with Lion that I tried it onto. Simple Movie X is great for the job, but at 40USD is a bit pricey. This one is not only good at the job but also cheap (free). I recommend this one :D
The MacPorts Project is an open-source community initiative to design an easy-to-use system for compiling, installing, and upgrading either command-line, X11 or Aqua based open-source software on the Mac OS X operating system. I really like the things that can be found on the port project.
Really nice and simple program that allows you to just burn whatever you want in the format you like. This makes use of a lot of unix tools readily available in Mac OS X, so, go and grab it while it is still hot!
SmillaEnlarger is an open source application that enlarges images using complex mathematical algorithms to figure out what was the image, the result is visually astonishing, it almost steps into the "it's magic!" realm.
TrueCrypt is free open-source disk encryption software for Windows 7/Vista/XP, Mac OS X and Linux. In case an attacker forces you to reveal the password, TrueCrypt provides plausible deniability. It sounds like a nice and great idea, and it just plainly works, it also has enough info for the uninitiated.
I know this is not strictly speaking Mac OS X software, but shouldn't you know it most of those tools are already installed in your Mac OS X and you can use them from the terminal! This is due to the heritage that Mac and Linux share bing Unix based OSes
TinkerTool is an application that gives you access to additional preference settings Apple has built into Mac OS X. This allows to activate hidden features in the operating system and in some of the applications delivered with the system.