When it comes to coding in CSS & HTML, I've always been a huge fan of Espresso, the fantastic application by MacRabbit. More after the jump.
I've been using Espresso for ages, but at a certain point, when I started coding in SCSS and having to compile to CSS, I switched to Coda instead. Compiling my code using CodeKit didn't go instantly in Espresso 2, and so I was loosing too much time. I had no choice really.
I must say I've been very accustomed to this way of working by now. Though with Espresso 3 being out, and its impressive list of new features, I might be switching back to my old favorite application again. One of the new functionalities in version 3 is called Dynamo, and from the sound of it, it might become exactly what I need. One of the things Dynamo can do is recompiling SCSS to CSS. So you see your update live. For now, I'm still using CodeKit since it also compresses and auto-prefixes my CSS, but who knows it might also be something Dynamo takes care of soon. Ideally CodeKit works hand-in-hand with an auto-refresh like it does in Coda.
I've always missed Espresso, not only because of its perfect GUI, but mostly because of its powerful Xray feature. X-what, you say? Never heard of it? Well, consider it the true perfection of the 'Inspect Element'. Together with the override function, not to mention the super fast way to find and edit your CSS, this feature is a true time saver. You can change CSS for live sites and see your design update in real-time. No need to publish, reload or even save. So it's totally non-destructive. These 2 features alone would make me switch to Espresso again in an instant.
Another cool feature, which was already in CSSEdit, but is now implemented in Espresso, is the text re-indentation. Having messed up code nicely re-indented the way you want it (yes you can set your style!) in an instance is just magic. Even minified CSS is no big deal. Pretty handy if you ask me.