Windows 8.1 / Windows 8 / Windows 7 / Windows Vista / Windows XP
Opera is one of the world's most famous Internet browsers. It has a substantial and very loyal following. It has such a following for a very good reason. Opera is arguably the fastest full-featured web browser in existence. It uses a specialized rendering engine that draws web pages onto the screen at a remarkable rate. It also includes a feature called "Opera Turbo," which sends your requests to a remote server that compresses web pages before sending them to you. The Opera Turbo servers remove extraneous HTML tags and reduce image quality to maximize performance on low-bandwidth connections. This makes it a godsend when connected via unreliable wireless networks or cellular Internet connections.
Opera was one of the first browsers to implement tabbed browsing. By using this feature, there is no need to clutter your screen with a dozen browser windows when you are multitasking heavily. Instead, each browser window can have numerous web pages open in it at once. The page to view is selected by clicking a "tab" at the top of the window, just under the menu bars. These tabs can be closed individually or rearranged as you see fit. It is also possible to save your current tag configuration so that you can come back to it later with minimal effort.
Opera was once a commercial product, but is now available for free download.