Opera is now available free of charge for windows. It is up to version 5.02 and has a small ad banner in the upper right corner. This windows version has the multiple browser windows in one main window feature of the other versions. It also has a built in e-mail client. A nice feature of the program is you can easily delete unwanted bookmarks with out having to confirm their deletion and it caches pages for easily going back and forth from a "hub" page. (Such as the main page of everything2.) The only parts of the program that I personally have a few minor issues with is that there is no stop button to press after the page has finshed loading. Meaning any animated gifs and midis playing have to be stopped indivudually (if you can). It doesn't display the border around images that are links, and that when you move your mouse over a picture with an alt="blah" tag the word blah fails to appear.

These few faults are minor and the browser is by far the best I have ever used.

Opera is also free for Linux but I havn't had the chance to use that version.