I know Apple's been sticking with nVidia lately, but they have a multi-screen technology too.
Those Macbook Pro clone hp's have it, allowing them to run two external monitors at the same time.
I'm not buying a new MBP until I can have two external 24's without an external piece of hardware.
EDIT: I was looking at a demo of HP's Envy 17 doing this, and it's ability to run 3 external displays hinges on using all three ports: minidisplay port. hdmi and vga (??!!??). Makes...