The latest version of Firefox, 3.1 Alpha, comes with the codename Shiretoko. Amongst the updates comes a great new feature, tab-switching. Pressing Ctrl+Tab displays a thumbnail view of the open tabs, along with the title of the page. This feature is similar to that of OS application-switching.
After the introduction of tabbed browsing, switching between multiple tabs has always been an issue. Many browsers have tried to solve this issue, however so for this looks to be the best.
Available @ Mozilla