If your surfing habits are anything like mine, you live inside tab browsing these days. Additionally, if you're on a Mac using Safari all the time, and dig OSX's Expose feature, then you will love this.
TabExpose melds tab browsing and expose into one sweet feature for Safari. One click or key tap, and it displays all your open tabs on your screen to navigate around them. Works on PPC & Intel Macs, on Leopard, Safari 3.x & 4.
Check it out - TabExpose