As a web designer having a good resource of icons is essential. The web is full of free icons, finding them is easy, finding the good ones is another matter. A good icon pack contains a broad selection of icons from documents to control icons.
For a serious and professional look the icons must be uniform and have a good color scheme. To save you the time I went through many free icons and selected the best looking ones and two premium sets. Premium icons are good if you want more control over the icon looks.