VistaIcons.com is a collection of free icon sets of over 2500 high quality icons in png and ico format. From VistaIcons.com you can freely download 256x256 PNG icons for Windows Vista and Windows 7.
Icons in Windows Vista visually represent programs, objects, actions, and concepts that help users to recognize and grasp meaning and purpose, identify places and items, and find their way through the UI with visual landmarks.
Icons have a maximum size of 256 x 256 pixels, making them suitable for high-DPI displays. These high-resolution icons allow for high visual quality in list views with large icons. This maximum size isn't required for icons used solely for menus, toolbars, glyphs or small symbols, or the notification area.
Not sure why this is only rated 2.1 - this is an excellent pack! Thanks!