If you like chrome appearance more than the boring looks of firefox, then this is the right post for you. You can change the appearance of firefox completely to firefox with an extension called Total ReChrome.
Total ReChrome configure the tabs to be located on the upper side to make it look identical to google chrome, it also adds glass effects in vista and perform some other useful tweaks.
Total ReChrome also moves the stop button on the left of the address to right side of the address to make it look exactly as google chrome.