There's not many laptops that can power more than one external display, but Fujitsu-Siemenes' Amilo Graphic Booster is an attractively designed external box with an ATI Radeon HD 3870with 512MB of memory built-in. It connects to your laptop via an external PCI-E cable, and once connected can drive up to three external monitors, as well as function as a simple 2-port USB hub.
Though there's no price, I really love this: I'm a firm believer in having as much screen real estate as possible, and my laptop is actually my main machine, even when I'm seated at a desk. Unfortunately, it looks like you need to buy its sister notebook to use it, the Amilo Notebook SA 3650. A pity, though there's no doubt Fujitsu makes fine laptops: I'd just like to see a cross-platform model.
Fujitsu Releases the 5.3-Lbs AMILO Sa 3650 Notebook with Radeon HD Graphics [Mobile Tech Review via Engadget]