Ctrl+Tab is handy for cycling through your Firefox tabs, but here i am showing you that with a small about:config tweak in Firefox 4, you can get really nice Alt+Tab style preview when you use it.
In Firefox 4 (b12 at least), if you hop into about:config and change browser.ctrlTab.previews to true, then Ctrl+Tab changes tabs with a very nice looking little popup.

This is really cool and amazing preview of all the currently opened tabs. Every user should try this trick. After applying this you will see your tabs like i n following image.

It’s a simple tweak that takes about 5 seconds, but boy does it make Ctrl+Tab switching much easier to use!