Cool, at last, I found the successor of tab-effect (an old Firefox 2.0 addon I used before): FoxTab, a cool Firefox 3.0 addon that brings 3D tab management. FoxTab offers several layouts for tab thumbnails displaying: stack, wall, grid, row and carousel.
You can download this addon right here: FoxTab 1.1.1.
Once installed, just launch Firefox and press [CTRL]+[Q] to start FoxTab. To switch tab, press [CTRL]+[TAB].
If you like eye-candy effects and Firefox modding, you’re going to love FoxTab!