Flat Icons & Icon Fonts. Icon fonts are awesome.
Other than the fact that they have to be single color, they are superior to using images as icons in every way. But which do you choose? There are loads of different sets out there. I'm going to attempt to round them all up here and keep this updated (this post has already been updated several times).
Colors. Icons. Favicon.ico Generator. Inspiration. Tutorials. Ressources. Sprite Cow.