Opera 10, the browser’s latest incarnation, ships with a visual tab bar that displays thumbnail previews when you expand it. This feature is particularly sleek and makes the browser even more beautiful.
If you’re a die-hard fan of Firefox, you can get the same features in your beloved browser by installing the Tab Sidebar addon.
Pop up its preference window after you’ve installed it, and change the orientation to top. Hit Ctrl + Shift + E and the visual tab bar pops up. Each thumbnail has back, forward, reload and close buttons as well.