There are certain apps that I use al the time. I mean ALL the time. Mail, Calendar, Safari, etc are some of the ones that you would expect, but one that you may not expect (for someone who does what I do) is PhotoShop. It's an incredibly powerful (and versatile) image-editing tool that allows you to do some really amazing things. The problem is, it can be expensive. It can be hard to justify the cost when the average user wouldn't use more than 20% of what it has to offer.
There are a lot of PhotoShop alternatives available on the market, but there's really only one that I would (highly) recommend for Mac users...
Pixelmator hasn't been around as long as PhotoShop, but it has made quite the splash in the Mac community. One look at the user interface (UI) and you will be impressed (at least I was). It's clear that PhotoShop was one of their inspirations. The other... Mac OS X. The interface is very Mac-like (clearly designed for Mac). This translates to "it's easy to use".
Outside of its ease-of-use, another benefit to using Pixelmator actually has very little to do with the software itself... they've done a great job at putting together some informative and helpful online video tutorials. Not only are they easy to follow along with, but they're very inspiring. You can check them out for free here.
Can you do everything in Pixelmator that you can do in PhotoShop? No. Is it designed for professionals? Earlier versions of Pixelmatr were probably not ready for prime time, but version 3.3 is very solid. With that in mind, as well as it's $30 price tag, it's an incredible PhotoShop alternative for the 95% of us. If you haven't done so already, it's worth a good, long look. You can download a free trial here.
Ready to buy? Download it from the Mac App Store here.
Bonus: Pixelmatr released an iOS version of their app recently that's also powerful and syncs files between iPhone, iPad and Mac using iCloud Drive. Check it out here.