iOS: Vox is one of our favourite music apps for Mac and today it's available for iOS alongside a new music locker service called LOOP.
Vox takes the simple, minimalist approach of the Mac app and applies it to the iPhone version. It's a simple interface with a grid or list view for your music, so it's easy to quickly get in and out of the app. That said, you can still do a lot with it. Vox supports nearly every audio format, including lossless and lossy formats, doesn't do any converting during playback, features a special engine to clear up sound, and integrates into Soundcloud. It also has a heap of equaliser settings to tweak your music.
Vox (Free) [iTunes App Store]