I originally bought Opera version 5, when it cost around US$30. It is a tabbed web browser, with a significant number of options to tweak (including my favorite, specifying what TLD and sub-domains to hit, like www and w3 and .com and .net and .org, instead of always assuming a site would be at www.example.com), and an amazing keyboard shortcut system. I can navigate entirely by the keyboard, selecting links and form items, switching tabs, opening links in new pages, etc.

Opera kept getting better, and finally the owners made one of the best decisions of all, distributing it as freeware. Now I gladly install Opera on any workstation that I control, and use it exclusively until I hit a site designed by idiots - which I can sometimes get around by simply hitting F12 and selecting "Identify as Internet Explorer".

Versatile, fast, great set of features, lots of customizations - and available on Windows and Linux.

I highly recommend Opera.