I'm currently working on a new iPhone app and starting to understand how difficult it is to build something that is both good looking and also simple to understand/use. There are so many small nuances to consider since there isn't a lot of real estate with which to get your point across. One of the most maddening things to get right are icons. People don't realize how difficult it is to build great looking icons from scratch. There are only a handful of apps that I consider beautiful and even among those, I have issues with the icons. After revision after revision of icons from my designer, I started to scour the web for examples of good icons. To my chagrin, the answer was staring me right in the face - Glyphish. Here was an extensive set of beautifully designed icons that are so simple and yet so clear in what the icon is supposed to represent. How good are these icons? They're used by little known companies like Google, Twitter, and a small phone manufacturer called Apple. The best part of it? $25 for a full pro license that doesn't require attribution and can be used in an unlimited number of projects (free version requires attribution, doesn't include Retina Display version of icons). I've seen icon sets costing four times as much that are no where near as clean and well designed. Kudos to Joseph Wain for creating these and providing them at a ridiculously cheap price.